chore(core): add an extra confirmation for non-1-of-1 Shamir backups

core/embed/rust/librust_qstr.h

@@ -432,6 +432,7 @@ static void _librust_qstrs(void) {
   MP_QSTR_reset__check_wallet_backup_title;
   MP_QSTR_reset__continue_with_next_share;
   MP_QSTR_reset__continue_with_share_template;
+  MP_QSTR_reset__create_x_of_y_shamir_backup_template;
   MP_QSTR_reset__finished_verifying_group_template;
   MP_QSTR_reset__finished_verifying_shares;
   MP_QSTR_reset__finished_verifying_wallet_backup;

core/mocks/trezortranslate_keys.pyi

@@ -577,6 +577,7 @@ class TR:
     reset__check_wallet_backup_title: str = "Check wallet backup"
     reset__continue_with_next_share: str = "Continue with the next share."
     reset__continue_with_share_template: str = "Continue with share #{0}."
+    reset__create_x_of_y_shamir_backup_template: str = "Do you want to create a {0} of {1} Shamir backup?"
     reset__finished_verifying_group_template: str = "You have finished verifying your recovery shares for group {0}."
     reset__finished_verifying_shares: str = "You have finished verifying your recovery shares."
     reset__finished_verifying_wallet_backup: str = "You have finished verifying your wallet backup."

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

@@ -167,7 +167,14 @@ async def backup_slip39_custom(
         # 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:
-        # TODO: a confirmation screen will be shown: "do you want to create a -of- Shamir backup?"
+        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:

core/translations/en.json

@@ -579,6 +579,7 @@
     "reset__check_backup_instructions": "Let's do a quick check of your backup.",
     "reset__continue_with_next_share": "Continue with the next share.",
     "reset__continue_with_share_template": "Continue with share #{0}.",
+    "reset__create_x_of_y_shamir_backup_template": "Do you want to create a {0} of {1} Shamir backup?",
     "reset__finished_verifying_group_template": "You have finished verifying your recovery shares for group {0}.",
     "reset__finished_verifying_wallet_backup": "You have finished verifying your wallet backup.",
     "reset__finished_verifying_shares": "You have finished verifying your recovery shares.",

tests/input_flows.py

@@ -1474,6 +1474,10 @@ class InputFlowSlip39CustomBackup(InputFlowBase):
         self.share_count = share_count
 
     def input_flow_tt(self) -> BRGeneratorType:
+        if self.share_count > 1:
+            yield  # Checklist
+            self.debug.press_yes()
+
         yield  # Confirm show seeds
         self.debug.press_yes()
 
@@ -1485,6 +1489,10 @@ class InputFlowSlip39CustomBackup(InputFlowBase):
         self.debug.press_yes()
 
     def input_flow_tr(self) -> BRGeneratorType:
+        if self.share_count > 1:
+            yield  # Checklist
+            self.debug.press_yes()
+
         yield  # Confirm show seeds
         self.debug.press_yes()
 
@@ -1496,6 +1504,10 @@ class InputFlowSlip39CustomBackup(InputFlowBase):
         self.debug.press_yes()
 
     def input_flow_t3t1(self) -> BRGeneratorType:
+        if self.share_count > 1:
+            yield  # Checklist
+            self.debug.press_yes()
+
         yield  # Confirm show seeds
         self.debug.press_yes()