diff --git a/common/protob/messages-management.proto b/common/protob/messages-management.proto
index d6008a5da..47905dec4 100644
--- a/common/protob/messages-management.proto
+++ b/common/protob/messages-management.proto
@@ -165,7 +165,7 @@ message WipeDevice {
  * @next Failure
  */
 message LoadDevice {
-    optional string mnemonic = 1;                           // seed encoded as BIP-39 mnemonic (12, 18 or 24 words)
+    repeated string mnemonics = 1;                          // seed encoded as mnemonic (12, 18 or 24 words for BIP39, 20 or 33 for SLIP39)
     optional hw.trezor.messages.common.HDNodeType node = 2; // BIP-32 node
     optional string pin = 3;                                // set PIN protection
     optional bool passphrase_protection = 4;                // enable master node encryption using passphrase
diff --git a/core/src/trezor/messages/LoadDevice.py b/core/src/trezor/messages/LoadDevice.py
index 285951745..936ae0b99 100644
--- a/core/src/trezor/messages/LoadDevice.py
+++ b/core/src/trezor/messages/LoadDevice.py
@@ -16,7 +16,7 @@ class LoadDevice(p.MessageType):
 
     def __init__(
         self,
-        mnemonic: str = None,
+        mnemonics: List[str] = None,
         node: HDNodeType = None,
         pin: str = None,
         passphrase_protection: bool = None,
@@ -25,7 +25,7 @@ class LoadDevice(p.MessageType):
         skip_checksum: bool = None,
         u2f_counter: int = None,
     ) -> None:
-        self.mnemonic = mnemonic
+        self.mnemonics = mnemonics if mnemonics is not None else []
         self.node = node
         self.pin = pin
         self.passphrase_protection = passphrase_protection
@@ -37,7 +37,7 @@ class LoadDevice(p.MessageType):
     @classmethod
     def get_fields(cls) -> Dict:
         return {
-            1: ('mnemonic', p.UnicodeType, 0),
+            1: ('mnemonics', p.UnicodeType, p.FLAG_REPEATED),
             2: ('node', HDNodeType, 0),
             3: ('pin', p.UnicodeType, 0),
             4: ('passphrase_protection', p.BoolType, 0),
diff --git a/python/trezorlib/messages/LoadDevice.py b/python/trezorlib/messages/LoadDevice.py
index 70b894ed3..db283519b 100644
--- a/python/trezorlib/messages/LoadDevice.py
+++ b/python/trezorlib/messages/LoadDevice.py
@@ -16,7 +16,7 @@ class LoadDevice(p.MessageType):
 
     def __init__(
         self,
-        mnemonic: str = None,
+        mnemonics: List[str] = None,
         node: HDNodeType = None,
         pin: str = None,
         passphrase_protection: bool = None,
@@ -25,7 +25,7 @@ class LoadDevice(p.MessageType):
         skip_checksum: bool = None,
         u2f_counter: int = None,
     ) -> None:
-        self.mnemonic = mnemonic
+        self.mnemonics = mnemonics if mnemonics is not None else []
         self.node = node
         self.pin = pin
         self.passphrase_protection = passphrase_protection
@@ -37,7 +37,7 @@ class LoadDevice(p.MessageType):
     @classmethod
     def get_fields(cls) -> Dict:
         return {
-            1: ('mnemonic', p.UnicodeType, 0),
+            1: ('mnemonics', p.UnicodeType, p.FLAG_REPEATED),
             2: ('node', HDNodeType, 0),
             3: ('pin', p.UnicodeType, 0),
             4: ('passphrase_protection', p.BoolType, 0),