feat(core): add ability to request backups with any number of groups/shares

common/protob/messages-management.proto

@@ -397,6 +397,12 @@ message ResetDevice {
  * @next Success
  */
 message BackupDevice {
+    optional uint32 group_threshold = 1;
+    message Slip39Group {
+        required uint32 member_threshold = 1;
+        required uint32 member_count = 2;
+    }
+    repeated Slip39Group groups = 2;
 }
 
 /**

core/.changelog.d/3636.added

@@ -0,0 +1 @@
+Added ability to request Shamir backups with any number of groups/shares.

core/src/apps/management/backup_device.py

@@ -1,9 +1,14 @@
 from typing import TYPE_CHECKING
 
+from trezor.enums import BackupType
+
 if TYPE_CHECKING:
     from trezor.messages import BackupDevice, Success
 
 
+BAK_T_BIP39 = BackupType.Bip39  # global_import_cache
+
+
 async def backup_device(msg: BackupDevice) -> Success:
     import storage.device as storage_device
     from trezor import wire
@@ -11,21 +16,37 @@ async def backup_device(msg: BackupDevice) -> Success:
 
     from apps.common import mnemonic
 
-    from .reset_device import backup_seed, layout
+    from .reset_device import backup_seed, backup_slip39_custom, layout
 
     if not storage_device.is_initialized():
         raise wire.NotInitialized("Device is not initialized")
     if not storage_device.needs_backup():
         raise wire.ProcessError("Seed already backed up")
 
-    mnemonic_secret, mnemonic_type = mnemonic.get()
+    mnemonic_secret, backup_type = mnemonic.get()
     if mnemonic_secret is None:
         raise RuntimeError
 
+    group_threshold = msg.group_threshold
+    groups = [(g.member_threshold, g.member_count) for g in msg.groups]
+
+    if group_threshold is not None:
+        if group_threshold < 1:
+            raise wire.DataError("group_threshold must be a positive integer")
+        if len(groups) < group_threshold:
+            raise wire.DataError("Not enough groups provided for group_threshold")
+        if backup_type == BAK_T_BIP39:
+            raise wire.ProcessError("Expected SLIP39 backup")
+    elif len(groups) > 0:
+        raise wire.DataError("group_threshold is missing")
+
     storage_device.set_unfinished_backup(True)
     storage_device.set_backed_up()
 
-    await backup_seed(mnemonic_type, mnemonic_secret)
+    if group_threshold is not None:
+        await backup_slip39_custom(mnemonic_secret, group_threshold, groups)
+    else:
+        await backup_seed(backup_type, mnemonic_secret)
 
     storage_device.set_unfinished_backup(False)
 

core/src/apps/management/reset_device/__init__.py

@@ -1,9 +1,11 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Sequence
 
 import storage
 import storage.device as storage_device
+from trezor import TR
 from trezor.crypto import slip39
 from trezor.enums import BackupType
+from trezor.ui.layouts import confirm_action
 from trezor.wire import ProcessError
 
 from . import layout
@@ -111,31 +113,19 @@ async def reset_device(msg: ResetDevice) -> Success:
 
 
 async def _backup_slip39_basic(encrypted_master_secret: bytes) -> None:
+    group_threshold = 1
+
     # get number of shares
     await layout.slip39_show_checklist(0, BAK_T_SLIP39_BASIC)
-    shares_count = await layout.slip39_prompt_number_of_shares()
+    share_count = await layout.slip39_prompt_number_of_shares()
 
     # get threshold
     await layout.slip39_show_checklist(1, BAK_T_SLIP39_BASIC)
-    threshold = await layout.slip39_prompt_threshold(shares_count)
+    share_threshold = await layout.slip39_prompt_threshold(share_count)
 
-    identifier = storage_device.get_slip39_identifier()
+    await backup_slip39_custom(
-    iteration_exponent = storage_device.get_slip39_iteration_exponent()
+        encrypted_master_secret, group_threshold, ((share_threshold, share_count),)
-    if identifier is None or iteration_exponent is None:
+    )
-        raise ValueError
-
-    # generate the mnemonics
-    mnemonics = slip39.split_ems(
-        1,  # Single Group threshold
-        [(threshold, shares_count)],  # Single Group threshold/count
-        identifier,
-        iteration_exponent,
-        encrypted_master_secret,
-    )[0]
-
-    # show and confirm individual shares
-    await layout.slip39_show_checklist(2, BAK_T_SLIP39_BASIC)
-    await layout.slip39_basic_show_and_confirm_shares(mnemonics)
 
 
 async def _backup_slip39_advanced(encrypted_master_secret: bytes) -> None:
@@ -155,6 +145,40 @@ async def _backup_slip39_advanced(encrypted_master_secret: bytes) -> None:
         share_threshold = await layout.slip39_prompt_threshold(share_count, i)
         groups.append((share_threshold, share_count))
 
+    await backup_slip39_custom(encrypted_master_secret, group_threshold, groups)
+
+
+async def backup_slip39_custom(
+    encrypted_master_secret: bytes,
+    group_threshold: int,
+    groups: Sequence[tuple[int, int]],
+) -> None:
+    mnemonics = await _get_slip39_mnemonics(encrypted_master_secret, group_threshold, groups)
+
+    # show and confirm individual shares
+    if len(groups) == 1 and groups[0][0] == 1 and groups[0][1] == 1:
+        # for a single 1-of-1 group, we use the same layouts as for BIP39
+        await layout.show_and_confirm_mnemonic(mnemonics[0][0])
+    else:
+        await confirm_action(
+            "warning_shamir_backup",
+            TR.reset__title_shamir_backup,
+            description=TR.reset__create_x_of_y_shamir_backup_template.format(
+                groups[0][0], groups[0][1]
+            ),
+            verb=TR.buttons__continue,
+        )
+        if len(groups) == 1:
+            await layout.slip39_basic_show_and_confirm_shares(mnemonics[0])
+        else:
+            await layout.slip39_advanced_show_and_confirm_shares(mnemonics)
+
+
+async def _get_slip39_mnemonics(
+    encrypted_master_secret: bytes,
+    group_threshold: int,
+    groups: Sequence[tuple[int, int]],
+):
     identifier = storage_device.get_slip39_identifier()
     iteration_exponent = storage_device.get_slip39_iteration_exponent()
     if identifier is None or iteration_exponent is None:
@@ -170,7 +194,11 @@ async def _backup_slip39_advanced(encrypted_master_secret: bytes) -> None:
     )
 
     # show and confirm individual shares
-    await layout.slip39_advanced_show_and_confirm_shares(mnemonics)
+    if len(groups) == 1:
+        await layout.slip39_show_checklist(2, BAK_T_SLIP39_BASIC)
+        await layout.slip39_basic_show_and_confirm_shares(mnemonics[0])
+    else:
+        await layout.slip39_advanced_show_and_confirm_shares(mnemonics)
 
 
 def _validate_reset_device(msg: ResetDevice) -> None:
@@ -184,7 +212,7 @@ def _validate_reset_device(msg: ResetDevice) -> None:
         BAK_T_SLIP39_BASIC,
         BAK_T_SLIP39_ADVANCED,
     ):
-        raise ProcessError("Backup type not implemented.")
+        raise ProcessError("Backup type not implemented")
     if backup_types.is_slip39_backup_type(backup_type):
         if msg.strength not in (128, 256):
             raise ProcessError("Invalid strength (has to be 128 or 256 bits)")

core/src/trezor/crypto/slip39.py

@@ -38,7 +38,7 @@ from trezor.crypto import random
 from trezor.errors import MnemonicError
 
 if TYPE_CHECKING:
-    from typing import Callable, Iterable
+    from typing import Callable, Collection, Iterable
 
     Indices = tuple[int, ...]
     MnemonicGroups = dict[int, tuple[int, set[tuple[int, bytes]]]]
@@ -174,7 +174,9 @@ def generate_random_identifier() -> int:
 
 def split_ems(
     group_threshold: int,  # The number of groups required to reconstruct the master secret.
-    groups: list[tuple[int, int]],  # A list of (member_threshold, member_count).
+    groups: Collection[
+        tuple[int, int]
+    ],  # A collection of (member_threshold, member_count).
     identifier: int,
     iteration_exponent: int,
     encrypted_master_secret: bytes,  # The encrypted master secret to split.

core/src/trezor/messages.py

@@ -2528,6 +2528,16 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class BackupDevice(protobuf.MessageType):
+        group_threshold: "int | None"
+        groups: "list[Slip39Group]"
+
+        def __init__(
+            self,
+            *,
+            groups: "list[Slip39Group] | None" = None,
+            group_threshold: "int | None" = None,
+        ) -> None:
+            pass
 
         @classmethod
         def is_type_of(cls, msg: Any) -> TypeGuard["BackupDevice"]:
@@ -2741,6 +2751,22 @@ if TYPE_CHECKING:
         def is_type_of(cls, msg: Any) -> TypeGuard["UnlockBootloader"]:
             return isinstance(msg, cls)
 
+    class Slip39Group(protobuf.MessageType):
+        member_threshold: "int"
+        member_count: "int"
+
+        def __init__(
+            self,
+            *,
+            member_threshold: "int",
+            member_count: "int",
+        ) -> None:
+            pass
+
+        @classmethod
+        def is_type_of(cls, msg: Any) -> TypeGuard["Slip39Group"]:
+            return isinstance(msg, cls)
+
     class DebugLinkDecision(protobuf.MessageType):
         button: "DebugButton | None"
         swipe: "DebugSwipeDirection | None"

legacy/firmware/protob/messages-management.options

@@ -26,6 +26,8 @@ LoadDevice.label                        max_size:33
 ResetDevice.language                    max_size:17
 ResetDevice.label                       max_size:33
 
+BackupDevice.groups                     type:FT_IGNORE
+
 Entropy.entropy                         max_size:1024
 
 EntropyAck.entropy                      max_size:128

python/.changelog.d/3636.added

@@ -0,0 +1 @@
+Added ability to request Shamir backups with any number of groups/shares.

python/src/trezorlib/cli/device.py

@@ -16,7 +16,7 @@
 
 import secrets
 import sys
-from typing import TYPE_CHECKING, Optional, Sequence
+from typing import TYPE_CHECKING, Optional, Sequence, Tuple
 
 import click
 
@@ -237,10 +237,17 @@ def setup(
 
 
 @cli.command()
+@click.option("-t", "--group-threshold", type=int)
+@click.option("-g", "--group", "groups", type=(int, int), multiple=True, metavar="T N")
 @with_client
-def backup(client: "TrezorClient") -> str:
+def backup(
+    client: "TrezorClient",
+    group_threshold: Optional[int] = None,
+    groups: Sequence[Tuple[int, int]] = (),
+) -> str:
     """Perform device seed backup."""
-    return device.backup(client)
+
+    return device.backup(client, group_threshold, groups)
 
 
 @cli.command()

python/src/trezorlib/device.py

@@ -19,7 +19,7 @@ from __future__ import annotations
 import os
 import time
 import warnings
-from typing import TYPE_CHECKING, Callable, Optional
+from typing import TYPE_CHECKING, Callable, Iterable, Optional
 
 from . import messages
 from .exceptions import Cancelled, TrezorException
@@ -264,8 +264,20 @@ def reset(
 
 @expect(messages.Success, field="message", ret_type=str)
 @session
-def backup(client: "TrezorClient") -> "MessageType":
+def backup(
-    ret = client.call(messages.BackupDevice())
+    client: "TrezorClient",
+    group_threshold: Optional[int] = None,
+    groups: Iterable[tuple[int, int]] = (),
+) -> "MessageType":
+    ret = client.call(
+        messages.BackupDevice(
+            group_threshold=group_threshold,
+            groups=[
+                messages.Slip39Group(member_threshold=t, member_count=c)
+                for t, c in groups
+            ],
+        )
+    )
     client.refresh_features()
     return ret
 

python/src/trezorlib/messages.py

@@ -3688,6 +3688,19 @@ class ResetDevice(protobuf.MessageType):
 
 class BackupDevice(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 34
+    FIELDS = {
+        1: protobuf.Field("group_threshold", "uint32", repeated=False, required=False, default=None),
+        2: protobuf.Field("groups", "Slip39Group", repeated=True, required=False, default=None),
+    }
+
+    def __init__(
+        self,
+        *,
+        groups: Optional[Sequence["Slip39Group"]] = None,
+        group_threshold: Optional["int"] = None,
+    ) -> None:
+        self.groups: Sequence["Slip39Group"] = groups if groups is not None else []
+        self.group_threshold = group_threshold
 
 
 class EntropyRequest(protobuf.MessageType):
@@ -3895,6 +3908,23 @@ class UnlockBootloader(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 96
 
 
+class Slip39Group(protobuf.MessageType):
+    MESSAGE_WIRE_TYPE = None
+    FIELDS = {
+        1: protobuf.Field("member_threshold", "uint32", repeated=False, required=True),
+        2: protobuf.Field("member_count", "uint32", repeated=False, required=True),
+    }
+
+    def __init__(
+        self,
+        *,
+        member_threshold: "int",
+        member_count: "int",
+    ) -> None:
+        self.member_threshold = member_threshold
+        self.member_count = member_count
+
+
 class DebugLinkDecision(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 100
     FIELDS = {

rust/trezor-client/src/protos/generated/messages_management.rs

@@ -7049,6 +7049,11 @@ impl ::protobuf::reflect::ProtobufValue for ResetDevice {
 // @@protoc_insertion_point(message:hw.trezor.messages.management.BackupDevice)
 #[derive(PartialEq,Clone,Default,Debug)]
 pub struct BackupDevice {
+    // message fields
+    // @@protoc_insertion_point(field:hw.trezor.messages.management.BackupDevice.group_threshold)
+    pub group_threshold: ::std::option::Option<u32>,
+    // @@protoc_insertion_point(field:hw.trezor.messages.management.BackupDevice.groups)
+    pub groups: ::std::vec::Vec<backup_device::Slip39Group>,
     // special fields
     // @@protoc_insertion_point(special_field:hw.trezor.messages.management.BackupDevice.special_fields)
     pub special_fields: ::protobuf::SpecialFields,
@@ -7065,9 +7070,38 @@ impl BackupDevice {
         ::std::default::Default::default()
     }
 
+    // optional uint32 group_threshold = 1;
+
+    pub fn group_threshold(&self) -> u32 {
+        self.group_threshold.unwrap_or(0)
+    }
+
+    pub fn clear_group_threshold(&mut self) {
+        self.group_threshold = ::std::option::Option::None;
+    }
+
+    pub fn has_group_threshold(&self) -> bool {
+        self.group_threshold.is_some()
+    }
+
+    // Param is passed by value, moved
+    pub fn set_group_threshold(&mut self, v: u32) {
+        self.group_threshold = ::std::option::Option::Some(v);
+    }
+
     fn generated_message_descriptor_data() -> ::protobuf::reflect::GeneratedMessageDescriptorData {
-        let mut fields = ::std::vec::Vec::with_capacity(0);
+        let mut fields = ::std::vec::Vec::with_capacity(2);
         let mut oneofs = ::std::vec::Vec::with_capacity(0);
+        fields.push(::protobuf::reflect::rt::v2::make_option_accessor::<_, _>(
+            "group_threshold",
+            |m: &BackupDevice| { &m.group_threshold },
+            |m: &mut BackupDevice| { &mut m.group_threshold },
+        ));
+        fields.push(::protobuf::reflect::rt::v2::make_vec_simpler_accessor::<_, _>(
+            "groups",
+            |m: &BackupDevice| { &m.groups },
+            |m: &mut BackupDevice| { &mut m.groups },
+        ));
         ::protobuf::reflect::GeneratedMessageDescriptorData::new_2::<BackupDevice>(
             "BackupDevice",
             fields,
@@ -7080,12 +7114,23 @@ impl ::protobuf::Message for BackupDevice {
     const NAME: &'static str = "BackupDevice";
 
     fn is_initialized(&self) -> bool {
+        for v in &self.groups {
+            if !v.is_initialized() {
+                return false;
+            }
+        };
         true
     }
 
     fn merge_from(&mut self, is: &mut ::protobuf::CodedInputStream<'_>) -> ::protobuf::Result<()> {
         while let Some(tag) = is.read_raw_tag_or_eof()? {
             match tag {
+                8 => {
+                    self.group_threshold = ::std::option::Option::Some(is.read_uint32()?);
+                },
+                18 => {
+                    self.groups.push(is.read_message()?);
+                },
                 tag => {
                     ::protobuf::rt::read_unknown_or_skip_group(tag, is, self.special_fields.mut_unknown_fields())?;
                 },
@@ -7098,12 +7143,25 @@ impl ::protobuf::Message for BackupDevice {
     #[allow(unused_variables)]
     fn compute_size(&self) -> u64 {
         let mut my_size = 0;
+        if let Some(v) = self.group_threshold {
+            my_size += ::protobuf::rt::uint32_size(1, v);
+        }
+        for value in &self.groups {
+            let len = value.compute_size();
+            my_size += 1 + ::protobuf::rt::compute_raw_varint64_size(len) + len;
+        };
         my_size += ::protobuf::rt::unknown_fields_size(self.special_fields.unknown_fields());
         self.special_fields.cached_size().set(my_size as u32);
         my_size
     }
 
     fn write_to_with_cached_sizes(&self, os: &mut ::protobuf::CodedOutputStream<'_>) -> ::protobuf::Result<()> {
+        if let Some(v) = self.group_threshold {
+            os.write_uint32(1, v)?;
+        }
+        for v in &self.groups {
+            ::protobuf::rt::write_message_field_with_cached_size(2, v, os)?;
+        };
         os.write_unknown_fields(self.special_fields.unknown_fields())?;
         ::std::result::Result::Ok(())
     }
@@ -7121,11 +7179,15 @@ impl ::protobuf::Message for BackupDevice {
     }
 
     fn clear(&mut self) {
+        self.group_threshold = ::std::option::Option::None;
+        self.groups.clear();
         self.special_fields.clear();
     }
 
     fn default_instance() -> &'static BackupDevice {
         static instance: BackupDevice = BackupDevice {
+            group_threshold: ::std::option::Option::None,
+            groups: ::std::vec::Vec::new(),
             special_fields: ::protobuf::SpecialFields::new(),
         };
         &instance
@@ -7149,6 +7211,193 @@ impl ::protobuf::reflect::ProtobufValue for BackupDevice {
     type RuntimeType = ::protobuf::reflect::rt::RuntimeTypeMessage<Self>;
 }
 
+/// Nested message and enums of message `BackupDevice`
+pub mod backup_device {
+    // @@protoc_insertion_point(message:hw.trezor.messages.management.BackupDevice.Slip39Group)
+    #[derive(PartialEq,Clone,Default,Debug)]
+    pub struct Slip39Group {
+        // message fields
+        // @@protoc_insertion_point(field:hw.trezor.messages.management.BackupDevice.Slip39Group.member_threshold)
+        pub member_threshold: ::std::option::Option<u32>,
+        // @@protoc_insertion_point(field:hw.trezor.messages.management.BackupDevice.Slip39Group.member_count)
+        pub member_count: ::std::option::Option<u32>,
+        // special fields
+        // @@protoc_insertion_point(special_field:hw.trezor.messages.management.BackupDevice.Slip39Group.special_fields)
+        pub special_fields: ::protobuf::SpecialFields,
+    }
+
+    impl<'a> ::std::default::Default for &'a Slip39Group {
+        fn default() -> &'a Slip39Group {
+            <Slip39Group as ::protobuf::Message>::default_instance()
+        }
+    }
+
+    impl Slip39Group {
+        pub fn new() -> Slip39Group {
+            ::std::default::Default::default()
+        }
+
+        // required uint32 member_threshold = 1;
+
+        pub fn member_threshold(&self) -> u32 {
+            self.member_threshold.unwrap_or(0)
+        }
+
+        pub fn clear_member_threshold(&mut self) {
+            self.member_threshold = ::std::option::Option::None;
+        }
+
+        pub fn has_member_threshold(&self) -> bool {
+            self.member_threshold.is_some()
+        }
+
+        // Param is passed by value, moved
+        pub fn set_member_threshold(&mut self, v: u32) {
+            self.member_threshold = ::std::option::Option::Some(v);
+        }
+
+        // required uint32 member_count = 2;
+
+        pub fn member_count(&self) -> u32 {
+            self.member_count.unwrap_or(0)
+        }
+
+        pub fn clear_member_count(&mut self) {
+            self.member_count = ::std::option::Option::None;
+        }
+
+        pub fn has_member_count(&self) -> bool {
+            self.member_count.is_some()
+        }
+
+        // Param is passed by value, moved
+        pub fn set_member_count(&mut self, v: u32) {
+            self.member_count = ::std::option::Option::Some(v);
+        }
+
+        pub(in super) fn generated_message_descriptor_data() -> ::protobuf::reflect::GeneratedMessageDescriptorData {
+            let mut fields = ::std::vec::Vec::with_capacity(2);
+            let mut oneofs = ::std::vec::Vec::with_capacity(0);
+            fields.push(::protobuf::reflect::rt::v2::make_option_accessor::<_, _>(
+                "member_threshold",
+                |m: &Slip39Group| { &m.member_threshold },
+                |m: &mut Slip39Group| { &mut m.member_threshold },
+            ));
+            fields.push(::protobuf::reflect::rt::v2::make_option_accessor::<_, _>(
+                "member_count",
+                |m: &Slip39Group| { &m.member_count },
+                |m: &mut Slip39Group| { &mut m.member_count },
+            ));
+            ::protobuf::reflect::GeneratedMessageDescriptorData::new_2::<Slip39Group>(
+                "BackupDevice.Slip39Group",
+                fields,
+                oneofs,
+            )
+        }
+    }
+
+    impl ::protobuf::Message for Slip39Group {
+        const NAME: &'static str = "Slip39Group";
+
+        fn is_initialized(&self) -> bool {
+            if self.member_threshold.is_none() {
+                return false;
+            }
+            if self.member_count.is_none() {
+                return false;
+            }
+            true
+        }
+
+        fn merge_from(&mut self, is: &mut ::protobuf::CodedInputStream<'_>) -> ::protobuf::Result<()> {
+            while let Some(tag) = is.read_raw_tag_or_eof()? {
+                match tag {
+                    8 => {
+                        self.member_threshold = ::std::option::Option::Some(is.read_uint32()?);
+                    },
+                    16 => {
+                        self.member_count = ::std::option::Option::Some(is.read_uint32()?);
+                    },
+                    tag => {
+                        ::protobuf::rt::read_unknown_or_skip_group(tag, is, self.special_fields.mut_unknown_fields())?;
+                    },
+                };
+            }
+            ::std::result::Result::Ok(())
+        }
+
+        // Compute sizes of nested messages
+        #[allow(unused_variables)]
+        fn compute_size(&self) -> u64 {
+            let mut my_size = 0;
+            if let Some(v) = self.member_threshold {
+                my_size += ::protobuf::rt::uint32_size(1, v);
+            }
+            if let Some(v) = self.member_count {
+                my_size += ::protobuf::rt::uint32_size(2, v);
+            }
+            my_size += ::protobuf::rt::unknown_fields_size(self.special_fields.unknown_fields());
+            self.special_fields.cached_size().set(my_size as u32);
+            my_size
+        }
+
+        fn write_to_with_cached_sizes(&self, os: &mut ::protobuf::CodedOutputStream<'_>) -> ::protobuf::Result<()> {
+            if let Some(v) = self.member_threshold {
+                os.write_uint32(1, v)?;
+            }
+            if let Some(v) = self.member_count {
+                os.write_uint32(2, v)?;
+            }
+            os.write_unknown_fields(self.special_fields.unknown_fields())?;
+            ::std::result::Result::Ok(())
+        }
+
+        fn special_fields(&self) -> &::protobuf::SpecialFields {
+            &self.special_fields
+        }
+
+        fn mut_special_fields(&mut self) -> &mut ::protobuf::SpecialFields {
+            &mut self.special_fields
+        }
+
+        fn new() -> Slip39Group {
+            Slip39Group::new()
+        }
+
+        fn clear(&mut self) {
+            self.member_threshold = ::std::option::Option::None;
+            self.member_count = ::std::option::Option::None;
+            self.special_fields.clear();
+        }
+
+        fn default_instance() -> &'static Slip39Group {
+            static instance: Slip39Group = Slip39Group {
+                member_threshold: ::std::option::Option::None,
+                member_count: ::std::option::Option::None,
+                special_fields: ::protobuf::SpecialFields::new(),
+            };
+            &instance
+        }
+    }
+
+    impl ::protobuf::MessageFull for Slip39Group {
+        fn descriptor() -> ::protobuf::reflect::MessageDescriptor {
+            static descriptor: ::protobuf::rt::Lazy<::protobuf::reflect::MessageDescriptor> = ::protobuf::rt::Lazy::new();
+            descriptor.get(|| super::file_descriptor().message_by_package_relative_name("BackupDevice.Slip39Group").unwrap()).clone()
+        }
+    }
+
+    impl ::std::fmt::Display for Slip39Group {
+        fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+            ::protobuf::text_format::fmt(self, f)
+        }
+    }
+
+    impl ::protobuf::reflect::ProtobufValue for Slip39Group {
+        type RuntimeType = ::protobuf::reflect::rt::RuntimeTypeMessage<Self>;
+    }
+}
+
 // @@protoc_insertion_point(message:hw.trezor.messages.management.EntropyRequest)
 #[derive(PartialEq,Clone,Default,Debug)]
 pub struct EntropyRequest {
@@ -10458,45 +10707,50 @@ static file_descriptor_proto_data: &'static [u8] = b"\
     \n\x0bu2f_counter\x18\x07\x20\x01(\rR\nu2fCounter\x12\x1f\n\x0bskip_back\
     up\x18\x08\x20\x01(\x08R\nskipBackup\x12\x1b\n\tno_backup\x18\t\x20\x01(\
     \x08R\x08noBackup\x12Q\n\x0bbackup_type\x18\n\x20\x01(\x0e2).hw.trezor.m\
-    essages.management.BackupType:\x05Bip39R\nbackupType\"\x0e\n\x0cBackupDe\
+    essages.management.BackupType:\x05Bip39R\nbackupType\"\xe5\x01\n\x0cBack\
-    vice\"\x10\n\x0eEntropyRequest\"&\n\nEntropyAck\x12\x18\n\x07entropy\x18\
+    upDevice\x12'\n\x0fgroup_threshold\x18\x01\x20\x01(\rR\x0egroupThreshold\
-    \x01\x20\x02(\x0cR\x07entropy\"\xd8\x03\n\x0eRecoveryDevice\x12\x1d\n\nw\
+    \x12O\n\x06groups\x18\x02\x20\x03(\x0b27.hw.trezor.messages.management.B\
-    ord_count\x18\x01\x20\x01(\rR\twordCount\x123\n\x15passphrase_protection\
+    ackupDevice.Slip39GroupR\x06groups\x1a[\n\x0bSlip39Group\x12)\n\x10membe\
-    \x18\x02\x20\x01(\x08R\x14passphraseProtection\x12%\n\x0epin_protection\
+    r_threshold\x18\x01\x20\x02(\rR\x0fmemberThreshold\x12!\n\x0cmember_coun\
-    \x18\x03\x20\x01(\x08R\rpinProtection\x12\x1e\n\x08language\x18\x04\x20\
+    t\x18\x02\x20\x02(\rR\x0bmemberCount\"\x10\n\x0eEntropyRequest\"&\n\nEnt\
-    \x01(\tR\x08languageB\x02\x18\x01\x12\x14\n\x05label\x18\x05\x20\x01(\tR\
+    ropyAck\x12\x18\n\x07entropy\x18\x01\x20\x02(\x0cR\x07entropy\"\xd8\x03\
-    \x05label\x12)\n\x10enforce_wordlist\x18\x06\x20\x01(\x08R\x0fenforceWor\
+    \n\x0eRecoveryDevice\x12\x1d\n\nword_count\x18\x01\x20\x01(\rR\twordCoun\
-    dlist\x12T\n\x04type\x18\x08\x20\x01(\x0e2@.hw.trezor.messages.managemen\
+    t\x123\n\x15passphrase_protection\x18\x02\x20\x01(\x08R\x14passphrasePro\
-    t.RecoveryDevice.RecoveryDeviceTypeR\x04type\x12\x1f\n\x0bu2f_counter\
+    tection\x12%\n\x0epin_protection\x18\x03\x20\x01(\x08R\rpinProtection\
-    \x18\t\x20\x01(\rR\nu2fCounter\x12\x17\n\x07dry_run\x18\n\x20\x01(\x08R\
+    \x12\x1e\n\x08language\x18\x04\x20\x01(\tR\x08languageB\x02\x18\x01\x12\
-    \x06dryRun\"Z\n\x12RecoveryDeviceType\x12%\n!RecoveryDeviceType_Scramble\
+    \x14\n\x05label\x18\x05\x20\x01(\tR\x05label\x12)\n\x10enforce_wordlist\
-    dWords\x10\0\x12\x1d\n\x19RecoveryDeviceType_Matrix\x10\x01\"\xc5\x01\n\
+    \x18\x06\x20\x01(\x08R\x0fenforceWordlist\x12T\n\x04type\x18\x08\x20\x01\
-    \x0bWordRequest\x12N\n\x04type\x18\x01\x20\x02(\x0e2:.hw.trezor.messages\
+    (\x0e2@.hw.trezor.messages.management.RecoveryDevice.RecoveryDeviceTypeR\
-    .management.WordRequest.WordRequestTypeR\x04type\"f\n\x0fWordRequestType\
+    \x04type\x12\x1f\n\x0bu2f_counter\x18\t\x20\x01(\rR\nu2fCounter\x12\x17\
-    \x12\x19\n\x15WordRequestType_Plain\x10\0\x12\x1b\n\x17WordRequestType_M\
+    \n\x07dry_run\x18\n\x20\x01(\x08R\x06dryRun\"Z\n\x12RecoveryDeviceType\
-    atrix9\x10\x01\x12\x1b\n\x17WordRequestType_Matrix6\x10\x02\"\x1d\n\x07W\
+    \x12%\n!RecoveryDeviceType_ScrambledWords\x10\0\x12\x1d\n\x19RecoveryDev\
-    ordAck\x12\x12\n\x04word\x18\x01\x20\x02(\tR\x04word\"0\n\rSetU2FCounter\
+    iceType_Matrix\x10\x01\"\xc5\x01\n\x0bWordRequest\x12N\n\x04type\x18\x01\
-    \x12\x1f\n\x0bu2f_counter\x18\x01\x20\x02(\rR\nu2fCounter\"\x13\n\x11Get\
+    \x20\x02(\x0e2:.hw.trezor.messages.management.WordRequest.WordRequestTyp\
-    NextU2FCounter\"1\n\x0eNextU2FCounter\x12\x1f\n\x0bu2f_counter\x18\x01\
+    eR\x04type\"f\n\x0fWordRequestType\x12\x19\n\x15WordRequestType_Plain\
-    \x20\x02(\rR\nu2fCounter\"\x11\n\x0fDoPreauthorized\"\x16\n\x14Preauthor\
+    \x10\0\x12\x1b\n\x17WordRequestType_Matrix9\x10\x01\x12\x1b\n\x17WordReq\
-    izedRequest\"\x15\n\x13CancelAuthorization\"\x9a\x02\n\x12RebootToBootlo\
+    uestType_Matrix6\x10\x02\"\x1d\n\x07WordAck\x12\x12\n\x04word\x18\x01\
-    ader\x12o\n\x0cboot_command\x18\x01\x20\x01(\x0e2=.hw.trezor.messages.ma\
+    \x20\x02(\tR\x04word\"0\n\rSetU2FCounter\x12\x1f\n\x0bu2f_counter\x18\
-    nagement.RebootToBootloader.BootCommand:\rSTOP_AND_WAITR\x0bbootCommand\
+    \x01\x20\x02(\rR\nu2fCounter\"\x13\n\x11GetNextU2FCounter\"1\n\x0eNextU2\
-    \x12'\n\x0ffirmware_header\x18\x02\x20\x01(\x0cR\x0efirmwareHeader\x123\
+    FCounter\x12\x1f\n\x0bu2f_counter\x18\x01\x20\x02(\rR\nu2fCounter\"\x11\
-    \n\x14language_data_length\x18\x03\x20\x01(\r:\x010R\x12languageDataLeng\
+    \n\x0fDoPreauthorized\"\x16\n\x14PreauthorizedRequest\"\x15\n\x13CancelA\
-    th\"5\n\x0bBootCommand\x12\x11\n\rSTOP_AND_WAIT\x10\0\x12\x13\n\x0fINSTA\
+    uthorization\"\x9a\x02\n\x12RebootToBootloader\x12o\n\x0cboot_command\
-    LL_UPGRADE\x10\x01\"\x10\n\x08GetNonce:\x04\x88\xb2\x19\x01\"#\n\x05Nonc\
+    \x18\x01\x20\x01(\x0e2=.hw.trezor.messages.management.RebootToBootloader\
-    e\x12\x14\n\x05nonce\x18\x01\x20\x02(\x0cR\x05nonce:\x04\x88\xb2\x19\x01\
+    .BootCommand:\rSTOP_AND_WAITR\x0bbootCommand\x12'\n\x0ffirmware_header\
-    \";\n\nUnlockPath\x12\x1b\n\taddress_n\x18\x01\x20\x03(\rR\x08addressN\
+    \x18\x02\x20\x01(\x0cR\x0efirmwareHeader\x123\n\x14language_data_length\
-    \x12\x10\n\x03mac\x18\x02\x20\x01(\x0cR\x03mac\"'\n\x13UnlockedPathReque\
+    \x18\x03\x20\x01(\r:\x010R\x12languageDataLength\"5\n\x0bBootCommand\x12\
-    st\x12\x10\n\x03mac\x18\x01\x20\x01(\x0cR\x03mac\"\x14\n\x12ShowDeviceTu\
+    \x11\n\rSTOP_AND_WAIT\x10\0\x12\x13\n\x0fINSTALL_UPGRADE\x10\x01\"\x10\n\
-    torial\"\x12\n\x10UnlockBootloader*>\n\nBackupType\x12\t\n\x05Bip39\x10\
+    \x08GetNonce:\x04\x88\xb2\x19\x01\"#\n\x05Nonce\x12\x14\n\x05nonce\x18\
-    \0\x12\x10\n\x0cSlip39_Basic\x10\x01\x12\x13\n\x0fSlip39_Advanced\x10\
+    \x01\x20\x02(\x0cR\x05nonce:\x04\x88\xb2\x19\x01\";\n\nUnlockPath\x12\
-    \x02*G\n\x10SafetyCheckLevel\x12\n\n\x06Strict\x10\0\x12\x10\n\x0cPrompt\
+    \x1b\n\taddress_n\x18\x01\x20\x03(\rR\x08addressN\x12\x10\n\x03mac\x18\
-    Always\x10\x01\x12\x15\n\x11PromptTemporarily\x10\x02*0\n\x10HomescreenF\
+    \x02\x20\x01(\x0cR\x03mac\"'\n\x13UnlockedPathRequest\x12\x10\n\x03mac\
-    ormat\x12\x08\n\x04Toif\x10\x01\x12\x08\n\x04Jpeg\x10\x02\x12\x08\n\x04T\
+    \x18\x01\x20\x01(\x0cR\x03mac\"\x14\n\x12ShowDeviceTutorial\"\x12\n\x10U\
-    oiG\x10\x03BB\n#com.satoshilabs.trezor.lib.protobufB\x17TrezorMessageMan\
+    nlockBootloader*>\n\nBackupType\x12\t\n\x05Bip39\x10\0\x12\x10\n\x0cSlip\
-    agement\x80\xa6\x1d\x01\
+    39_Basic\x10\x01\x12\x13\n\x0fSlip39_Advanced\x10\x02*G\n\x10SafetyCheck\
+    Level\x12\n\n\x06Strict\x10\0\x12\x10\n\x0cPromptAlways\x10\x01\x12\x15\
+    \n\x11PromptTemporarily\x10\x02*0\n\x10HomescreenFormat\x12\x08\n\x04Toi\
+    f\x10\x01\x12\x08\n\x04Jpeg\x10\x02\x12\x08\n\x04ToiG\x10\x03BB\n#com.sa\
+    toshilabs.trezor.lib.protobufB\x17TrezorMessageManagement\x80\xa6\x1d\
+    \x01\
 ";
 
 /// `FileDescriptorProto` object which was a source for this generated file
@@ -10515,7 +10769,7 @@ pub fn file_descriptor() -> &'static ::protobuf::reflect::FileDescriptor {
         let generated_file_descriptor = generated_file_descriptor_lazy.get(|| {
             let mut deps = ::std::vec::Vec::with_capacity(1);
             deps.push(super::messages::file_descriptor().clone());
-            let mut messages = ::std::vec::Vec::with_capacity(44);
+            let mut messages = ::std::vec::Vec::with_capacity(45);
             messages.push(Initialize::generated_message_descriptor_data());
             messages.push(GetFeatures::generated_message_descriptor_data());
             messages.push(Features::generated_message_descriptor_data());
@@ -10560,6 +10814,7 @@ pub fn file_descriptor() -> &'static ::protobuf::reflect::FileDescriptor {
             messages.push(UnlockedPathRequest::generated_message_descriptor_data());
             messages.push(ShowDeviceTutorial::generated_message_descriptor_data());
             messages.push(UnlockBootloader::generated_message_descriptor_data());
+            messages.push(backup_device::Slip39Group::generated_message_descriptor_data());
             let mut enums = ::std::vec::Vec::with_capacity(8);
             enums.push(BackupType::generated_enum_descriptor_data());
             enums.push(SafetyCheckLevel::generated_enum_descriptor_data());

tests/click_tests/reset.py

@@ -38,6 +38,13 @@ def confirm_read(debug: "DebugLink", middle_r: bool = False) -> None:
             debug.press_right(wait=True)
 
 
+def cancel_backup(debug: "DebugLink", middle_r: bool = False) -> None:
+    if debug.model in (models.T2T1, models.T3T1):
+        debug.click(buttons.CANCEL, wait=True)
+    elif debug.model in (models.T2B1,):
+        debug.press_left(wait=True)
+
+
 def set_selection(debug: "DebugLink", button: tuple[int, int], diff: int) -> None:
     if debug.model in (models.T2T1, models.T3T1):
         assert "NumberInputDialog" in debug.read_layout().all_components()

tests/click_tests/test_backup_slip39_custom.py

@@ -0,0 +1,118 @@
+# This file is part of the Trezor project.
+#
+# Copyright (C) 2012-2024 SatoshiLabs and contributors
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the License along with this library.
+# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+from trezorlib import device, messages
+
+from ..common import EXTERNAL_ENTROPY, WITH_MOCK_URANDOM, generate_entropy
+from . import reset
+
+if TYPE_CHECKING:
+    from ..device_handler import BackgroundDeviceHandler
+
+
+pytestmark = [pytest.mark.skip_t1b1]
+
+
+@pytest.mark.parametrize(
+    "group_threshold, share_threshold, share_count",
+    [
+        pytest.param(1, 1, 1, id="1of1"),
+        pytest.param(1, 2, 3, id="2of3"),
+        pytest.param(1, 5, 5, id="5of5"),
+    ],
+)
+@pytest.mark.setup_client(uninitialized=True)
+@WITH_MOCK_URANDOM
+def test_backup_slip39_custom(
+    device_handler: "BackgroundDeviceHandler",
+    group_threshold: int,
+    share_threshold: int,
+    share_count: int,
+):
+    features = device_handler.features()
+    debug = device_handler.debuglink()
+
+    assert features.initialized is False
+
+    device_handler.run(
+        device.reset,
+        strength=128,
+        backup_type=messages.BackupType.Slip39_Basic,
+        pin_protection=False,
+    )
+
+    # confirm new wallet
+    reset.confirm_new_wallet(debug)
+
+    # cancel back up
+    reset.cancel_backup(debug)
+
+    # confirm cancel
+    reset.cancel_backup(debug)
+
+    assert device_handler.result() == "Initialized"
+
+    device_handler.run(
+        device.backup,
+        group_threshold=group_threshold,
+        groups=[(share_threshold, share_count)],
+    )
+
+    # confirm checklist
+    reset.confirm_read(debug)
+
+    # confirm backup warning
+    reset.confirm_read(debug, middle_r=True)
+
+    if share_count > 1:
+        # confirm shamir warning
+        reset.confirm_read(debug, middle_r=True)
+
+    all_words: list[str] = []
+    for _ in range(share_count):
+        # read words
+        words = reset.read_words(debug, messages.BackupType.Slip39_Basic)
+
+        # confirm words
+        reset.confirm_words(debug, words)
+
+        # confirm share checked
+        reset.confirm_read(debug)
+
+        all_words.append(" ".join(words))
+
+    # confirm backup done
+    reset.confirm_read(debug)
+
+    # generate secret locally
+    internal_entropy = debug.state().reset_entropy
+    assert internal_entropy is not None
+    secret = generate_entropy(128, internal_entropy, EXTERNAL_ENTROPY)
+
+    # validate that all combinations will result in the correct master secret
+    reset.validate_mnemonics(all_words[:share_threshold], secret)
+
+    assert device_handler.result() == "Seed successfully backed up"
+    features = device_handler.features()
+    assert features.initialized is True
+    assert features.needs_backup is False
+    assert features.pin_protection is False
+    assert features.passphrase_protection is False
+    assert features.backup_type is messages.BackupType.Slip39_Basic

tests/common.py

@@ -58,6 +58,8 @@ MNEMONIC_SLIP39_ADVANCED_33 = [
     "wildlife deal beard romp alcohol space mild usual clothes union nuclear testify course research heat listen task location thank hospital slice smell failure fawn helpful priest ambition average recover lecture process dough stadium",
     "wildlife deal acrobat romp anxiety axis starting require metric flexible geology game drove editor edge screw helpful have huge holy making pitch unknown carve holiday numb glasses survive already tenant adapt goat fangs",
 ]
+MNEMONIC_SLIP39_CUSTOM_1of1 = ["tolerate flexible academic academic average dwarf square home promise aspect temple cluster roster forward hand unfair tenant emperor ceramic element forget perfect knit adapt review usual formal receiver typical pleasure duke yield party"]
+MNEMONIC_SLIP39_CUSTOM_SECRET = "3439316237393562383066633231636364663436366330666263393863386663"
 # External entropy mocked as received from trezorlib.
 EXTERNAL_ENTROPY = b"zlutoucky kun upel divoke ody" * 2
 # fmt: on

tests/device_tests/test_msg_backup_device.py

@@ -25,12 +25,15 @@ from trezorlib.exceptions import TrezorFailure
 from ..common import (
     MNEMONIC12,
     MNEMONIC_SLIP39_ADVANCED_20,
+    MNEMONIC_SLIP39_CUSTOM_SECRET,
     MNEMONIC_SLIP39_BASIC_20_3of6,
+    MNEMONIC_SLIP39_CUSTOM_1of1,
 )
 from ..input_flows import (
     InputFlowBip39Backup,
     InputFlowSlip39AdvancedBackup,
     InputFlowSlip39BasicBackup,
+    InputFlowSlip39CustomBackup,
 )
 
 
@@ -111,6 +114,36 @@ def test_backup_slip39_advanced(client: Client, click_info: bool):
     assert expected_ms == actual_ms
 
 
+@pytest.mark.skip_t1b1
+@pytest.mark.setup_client(needs_backup=True, mnemonic=MNEMONIC_SLIP39_CUSTOM_1of1[0])
+@pytest.mark.parametrize(
+    "share_threshold,share_count",
+    [(1, 1), (2, 2), (3, 5)],
+    ids=["1_of_1", "2_of_2", "3_of_5"],
+)
+def test_backup_slip39_custom(client: Client, share_threshold, share_count):
+    assert client.features.needs_backup is True
+
+    with client:
+        IF = InputFlowSlip39CustomBackup(client, share_count)
+        client.set_input_flow(IF.get())
+        device.backup(
+            client, group_threshold=1, groups=[(share_threshold, share_count)]
+        )
+
+    client.init_device()
+    assert client.features.initialized is True
+    assert client.features.needs_backup is False
+    assert client.features.unfinished_backup is False
+    assert client.features.no_backup is False
+
+    assert len(IF.mnemonics) == share_count
+    assert (
+        shamir.combine_mnemonics(IF.mnemonics[-share_threshold:]).hex()
+        == MNEMONIC_SLIP39_CUSTOM_SECRET
+    )
+
+
 # we only test this with bip39 because the code path is always the same
 @pytest.mark.setup_client(no_backup=True)
 def test_no_backup_fails(client: Client):

tests/input_flows.py

@@ -1211,12 +1211,13 @@ class InputFlowBip39ResetFailedCheck(InputFlowBase):
         self.debug.press_yes()
 
 
-def load_5_shares(
+def load_N_shares(
     debug: DebugLink,
+    n: int,
 ) -> Generator[None, "messages.ButtonRequest", list[str]]:
     mnemonics: list[str] = []
 
-    for _ in range(5):
+    for _ in range(n):
         # Phrase screen
         mnemonic = yield from read_and_confirm_mnemonic(debug)
         assert mnemonic is not None
@@ -1254,7 +1255,7 @@ class InputFlowSlip39BasicBackup(InputFlowBase):
         self.debug.press_yes()
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # Confirm backup
         assert br.code == B.Success
@@ -1279,7 +1280,7 @@ class InputFlowSlip39BasicBackup(InputFlowBase):
         self.debug.press_yes()
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # Confirm backup
         assert br.code == B.Success
@@ -1304,7 +1305,7 @@ class InputFlowSlip39BasicBackup(InputFlowBase):
         self.debug.press_yes()
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # Confirm backup
         assert br.code == B.Success
@@ -1328,7 +1329,7 @@ class InputFlowSlip39BasicResetRecovery(InputFlowBase):
         yield from click_through(self.debug, screens=8, code=B.ResetDevice)
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # safety warning
         assert br.code == B.Success
@@ -1357,7 +1358,7 @@ class InputFlowSlip39BasicResetRecovery(InputFlowBase):
         self.debug.press_yes()
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # Confirm backup
         assert br.code == B.Success
@@ -1375,13 +1376,59 @@ class InputFlowSlip39BasicResetRecovery(InputFlowBase):
         yield from click_through(self.debug, screens=8, code=B.ResetDevice)
 
         # Mnemonic phrases
-        self.mnemonics = yield from load_5_shares(self.debug)
+        self.mnemonics = yield from load_N_shares(self.debug, 5)
 
         br = yield  # safety warning
         assert br.code == B.Success
         self.debug.press_yes()
 
 
+class InputFlowSlip39CustomBackup(InputFlowBase):
+    def __init__(self, client: Client, share_count: int):
+        super().__init__(client)
+        self.mnemonics: list[str] = []
+        self.share_count = share_count
+
+    def input_flow_tt(self) -> BRGeneratorType:
+        yield  # Checklist
+        self.debug.press_yes()
+        yield  # Confirm show seeds
+        self.debug.press_yes()
+
+        # Mnemonic phrases
+        self.mnemonics = yield from load_N_shares(self.debug, self.share_count)
+
+        br = yield  # Confirm backup
+        assert br.code == B.Success
+        self.debug.press_yes()
+
+    def input_flow_tr(self) -> BRGeneratorType:
+        yield  # Checklist
+        self.debug.press_yes()
+        yield  # Confirm show seeds
+        self.debug.press_yes()
+
+        # Mnemonic phrases
+        self.mnemonics = yield from load_N_shares(self.debug, self.share_count)
+
+        br = yield  # Confirm backup
+        assert br.code == B.Success
+        self.debug.press_yes()
+
+    def input_flow_t3t1(self) -> BRGeneratorType:
+        yield  # Checklist
+        self.debug.press_yes()
+        yield  # Confirm show seeds
+        self.debug.press_yes()
+
+        # Mnemonic phrases
+        self.mnemonics = yield from load_N_shares(self.debug, self.share_count)
+
+        br = yield  # Confirm backup
+        assert br.code == B.Success
+        self.debug.press_yes()
+
+
 def load_5_groups_5_shares(
     debug: DebugLink,
 ) -> Generator[None, "messages.ButtonRequest", list[str]]:

tests/ui_tests/fixtures.json

@@ -835,6 +835,9 @@
 "T3T1_en_test_autolock.py::test_dryrun_enter_word_slowly": "be557c3e4e0492d0b884d4ed549d3ae18e6175b74b5945e7ab6f2f96aab58748",
 "T3T1_en_test_autolock.py::test_dryrun_locks_at_number_of_words": "700aa42142055535b4123d84f6d307a0589b43600c2dec525312d06c2af9aa18",
 "T3T1_en_test_autolock.py::test_dryrun_locks_at_word_entry": "736652b5298a7a4ee2e51282323d1150c9844b6f7b738f421ac4ad3a83d0788d",
+"T3T1_en_test_backup_slip39_custom.py::test_backup_slip39_custom[1of1]": "b13e22bddd80296bb0d08dff4bc94dad287c40247045eb779b88ba5c53050507",
+"T3T1_en_test_backup_slip39_custom.py::test_backup_slip39_custom[2of3]": "ebab6dc1bbf5648693ff34ffece0b67d829d44ac03a751c72dcf623b2cd2c8ba",
+"T3T1_en_test_backup_slip39_custom.py::test_backup_slip39_custom[5of5]": "aadf5b948d034af305b275fd0d837619b8f133039b4ed431fa31fd65cc2e143e",
 "T3T1_en_test_lock.py::test_hold_to_lock": "9d60d7aa2fbe6a0de14379e02ea825fbf9e21471596498f7be686f2538391f1d",
 "T3T1_en_test_passphrase_tt.py::test_cycle_through_last_character": "2a8d54c8014cc0c1bf46c0e4b58d6a002009b62aa8b92db663f88af0ad2f5e19",
 "T3T1_en_test_passphrase_tt.py::test_passphrase_click_same_button_many_times": "6a579067b4395a260d173e78643b67ac701304ea833a112cb2da1bce94cbb102",
@@ -5096,11 +5099,14 @@
 "T3T1_en_test_msg_applysettings.py::test_experimental_features": "e774f4de022f48caacc2445b1994ac19dce7a6155b4224ae7eb727ffc8975ca9",
 "T3T1_en_test_msg_applysettings.py::test_label_too_long": "80a6e289138a604cf351a29511cf6f85e2243591317894703152787e1351a1a3",
 "T3T1_en_test_msg_applysettings.py::test_safety_checks": "b129e0ba2e3c7ac836b3bb4b0bc8ded1c922eba054b42b434d10499fc780ea2b",
-"T3T1_en_test_msg_backup_device.py::test_backup_bip39": "dfb5ff96727714c4d8115f9dee8d76d9cb40c46a6a5e693118cb8e332e0124ab",
+"T3T1_en_test_msg_backup_device.py::test_backup_bip39": "429a141f97ad5a7b857985fcba60a7ac35e09e6ea54013203d80cb63deef8638",
-"T3T1_en_test_msg_backup_device.py::test_backup_slip39_advanced[click_info]": "24ef4ff564a1d024deb4efa7b2fff91fa69892a6373f566cc5c4d86045c0c853",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_advanced[click_info]": "75f8fb63ed22a2e9983a9d60488d6cb87bde792ed7b00b67f1754ef5bfa8910a",
-"T3T1_en_test_msg_backup_device.py::test_backup_slip39_advanced[no_click_info]": "ca4836dd39f2398401fe2001a6cb7bf389f83fcd8e7770a65ca79b6840fe176a",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_advanced[no_click_info]": "31f143785472dad5adc46df21cf80ae3210c30c22fc719d9f56446d1915a36e8",
-"T3T1_en_test_msg_backup_device.py::test_backup_slip39_basic[click_info]": "01af0780579b900211698fdaa68a34f4339fa516f152dfd013e210f96b02f5e1",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_basic[click_info]": "63db4c01cc1abddf73ece3c61d9d0de6bfd6499559e01bc58c2981f416a922f8",
-"T3T1_en_test_msg_backup_device.py::test_backup_slip39_basic[no_click_info]": "efd5fa4a4a87e6ac6e6b6b2c819d3d40711e7aff0340d1bab27794c333caa8d0",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_basic[no_click_info]": "f1cab327533697803793725144e42200106e05f1d81b75ff0a8eb55453a37dfa",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_custom[2_of_2]": "b0c0eccecc9e7a84ce9af7fca76d6edce2b1fd0ea48b41354cd0a2f31b8ff604",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_custom[1_of_1]": "8e6156bc4caf5f75de7c164844de9405e6c08bb74352dc6976a8d93dbc994e53",
+"T3T1_en_test_msg_backup_device.py::test_backup_slip39_custom[3_of_5]": "61014a41b3c84831b6c82d0d3f8527452fed48f52cde4737b66f62a72bac3d5e",
 "T3T1_en_test_msg_backup_device.py::test_interrupt_backup_fails": "ae147498028d68aa71c7337544e4a5049c4c943897f905c6fe29e88e5c3ab056",
 "T3T1_en_test_msg_backup_device.py::test_no_backup_fails": "fada9d38ec099b3c6a4fd8bf994bb1f3431e40085128b4e0cd9deb8344dec53e",
 "T3T1_en_test_msg_backup_device.py::test_no_backup_show_entropy_fails": "c47cfc38ee8a29b79808336a6f99b037f4a760b907bb9c680a554f92a194d262",
@@ -8130,6 +8136,9 @@
 "TR_en_test_autolock.py::test_dryrun_enter_word_slowly": "f35d159c13b36c428e68969bbeb87fb4bdbfa6c21eb98985b5832849938d6934",
 "TR_en_test_autolock.py::test_dryrun_locks_at_number_of_words": "df7a17ab9cd2c617ce22a615e1da9bedee41f978459cbe103f2eecb8dfe8db12",
 "TR_en_test_autolock.py::test_dryrun_locks_at_word_entry": "53b39b3ff0548a91e87ac3391462850e4f6060fa1a19ae873eca6fc5cce8dbb2",
+"TR_en_test_backup_slip39_custom.py::test_backup_slip39_custom[1of1]": "9e620acfff4ef1442996b81c1fd9c73d20490c2deecc6bc05aa0b665d9cd217c",
+"TR_en_test_backup_slip39_custom.py::test_backup_slip39_custom[2of3]": "aa0d1382ef0f2e16e24d0afbd25a105f572cd4f17d91dd44ca6a3f46a60bf6c4",
+"TR_en_test_backup_slip39_custom.py::test_backup_slip39_custom[5of5]": "5586a21ef466d85077021c289690f22afe787445523b29900f49ec03468598d8",
 "TR_en_test_lock.py::test_hold_to_lock": "83e2d055215b03150069d9fcb3aee6dc3f78a0d2bc43d8133425bf6b000c191d",
 "TR_en_test_passphrase_tr.py::test_cancel": "4a79e82b3ddf23c087e70767f2c4d4720f980370e22be209189d4ed42a453ee8",
 "TR_en_test_passphrase_tr.py::test_passphrase_delete": "28468562292a54f2d8cc954129c6b1859c267bc5a9b94f9b406352e71a4c8036",
@@ -15206,6 +15215,9 @@
 "TT_en_test_autolock.py::test_dryrun_enter_word_slowly": "140ff1c01d0d27ade29e88af481a9a24385fbe01058bdbf35f2fa20c19e0c386",
 "TT_en_test_autolock.py::test_dryrun_locks_at_number_of_words": "f9a5c8f92ca3b0b9545a9a5b3cf8df4de9943fbe45de113aa6f970d60b3b9b49",
 "TT_en_test_autolock.py::test_dryrun_locks_at_word_entry": "2ea54adc6df443f758a6395b6b443fbfe5931cbd62a321504de9ae453aff8ca8",
+"TT_en_test_backup_slip39_custom.py::test_backup_slip39_custom[1of1]": "6c33232fdff24175a489c83507bcde9bd859cc2d7f1ca687e154befd0cd2b883",
+"TT_en_test_backup_slip39_custom.py::test_backup_slip39_custom[2of3]": "20bdb47f4150af61b2a64927f7df2f49fedf9d02442d103c2833bddcc57f9f93",
+"TT_en_test_backup_slip39_custom.py::test_backup_slip39_custom[5of5]": "97fb33be7f98498b0acfcade1e5333475c9e6dce131ca7bdde3a54cf72c595fe",
 "TT_en_test_lock.py::test_hold_to_lock": "a5739f92ae28fc57769e444408ce5b58223d0d33b368022ef78ea68e0f8c9b80",
 "TT_en_test_passphrase_tt.py::test_cycle_through_last_character": "2a8d54c8014cc0c1bf46c0e4b58d6a002009b62aa8b92db663f88af0ad2f5e19",
 "TT_en_test_passphrase_tt.py::test_passphrase_click_same_button_many_times": "6a579067b4395a260d173e78643b67ac701304ea833a112cb2da1bce94cbb102",
@@ -19593,11 +19605,14 @@
 "TT_en_test_msg_applysettings.py::test_experimental_features": "523f74db7f660c261507dfdd92285981869af72c9ba391c4dfedb3f06ccf40ad",
 "TT_en_test_msg_applysettings.py::test_label_too_long": "80a6e289138a604cf351a29511cf6f85e2243591317894703152787e1351a1a3",
 "TT_en_test_msg_applysettings.py::test_safety_checks": "b129e0ba2e3c7ac836b3bb4b0bc8ded1c922eba054b42b434d10499fc780ea2b",
-"TT_en_test_msg_backup_device.py::test_backup_bip39": "3b90a1c3383b3afa2c321109e1088b2e33d976a9f75db3b013456d52c85ae5d2",
+"TT_en_test_msg_backup_device.py::test_backup_bip39": "09c32059eea15ce17dd07bc34f09ca335e8a6cee573fef0095cf2105932a078a",
-"TT_en_test_msg_backup_device.py::test_backup_slip39_advanced[click_info]": "2738a2e8fb890f7f2f5857cd9af0d3f6eac9fbf71dc299c829b1ba6a1209b712",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_advanced[click_info]": "5007dfedc1b4420b096f76d33acc9bcf77ec6083d54ca59571f5d225dfb2a33b",
-"TT_en_test_msg_backup_device.py::test_backup_slip39_advanced[no_click_info]": "503c667f02e099102be7c9bf14e771b5e27f41eabebdf7269389c9d9b33016ae",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_advanced[no_click_info]": "4f13e0550f8e06481fd4f59d722d3893ea904f85fb20ec8018344347492aff1c",
-"TT_en_test_msg_backup_device.py::test_backup_slip39_basic[click_info]": "65b98eb420a3b4a5128dc686f491a55b460205db7e1e1bb2828a3d6998af5466",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_basic[click_info]": "b432bf3671b15fdcfb92113fcef0e95671c3d7beaae70b25a87d090d30f9a079",
-"TT_en_test_msg_backup_device.py::test_backup_slip39_basic[no_click_info]": "a3c26090183f9b150cd0caccfa2a4ba9833de718868777cc1e6f255ddda8a94f",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_basic[no_click_info]": "4a6f3fdd5d7ae36e6b5ad84faa5385565fd13f4ce3f7d915fa16c2184f99ebbd",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_custom[2_of_2]": "53788010ec0f9c81ea07828ae32425c3d38a1d35789aa91d3163e117fa2cbe99",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_custom[1_of_1]": "e17b49d05f231444684b0ebad638456b4b6d7b0ae195180778c3f687b7d0ca7d",
+"TT_en_test_msg_backup_device.py::test_backup_slip39_custom[3_of_5]": "ebc007c9801856ad27dd6332b7dc5413189191268e10fcf5604203b75d8c52ed",
 "TT_en_test_msg_backup_device.py::test_interrupt_backup_fails": "ae147498028d68aa71c7337544e4a5049c4c943897f905c6fe29e88e5c3ab056",
 "TT_en_test_msg_backup_device.py::test_no_backup_fails": "fada9d38ec099b3c6a4fd8bf994bb1f3431e40085128b4e0cd9deb8344dec53e",
 "TT_en_test_msg_backup_device.py::test_no_backup_show_entropy_fails": "001377ce61dcd189e6a9d17e20dcd71130e951dc3314b40ff26f816bd9355bdd",