diff --git a/src/apps/wallet/sign_tx/scripts.py b/src/apps/wallet/sign_tx/scripts.py
index 7a4bb03cc7..1b55fd3f1b 100644
--- a/src/apps/wallet/sign_tx/scripts.py
+++ b/src/apps/wallet/sign_tx/scripts.py
@@ -158,8 +158,9 @@ def get_p2wsh_witness(multisig: MultisigRedeemScriptType, signature: bytes, sign
     for s in signatures:
         append_signature(w, s, sighash)  # size of the witness included
 
-    redeem_script = script_multisig(multisig_get_pubkeys(multisig), multisig.m)
-
+    # redeem script
+    pubkeys = multisig_get_pubkeys(multisig)
+    redeem_script = script_multisig(pubkeys, multisig.m)
     write_varint(w, len(redeem_script))
     write_bytes(w, redeem_script)
     return w
@@ -167,22 +168,28 @@ def get_p2wsh_witness(multisig: MultisigRedeemScriptType, signature: bytes, sign
 
 # -------------------------- Multisig --------------------------
 
-def input_script_multisig(current_signature, other_signatures, pubkeys, m: int, sighash: int):
+def input_script_multisig(multisig: MultisigRedeemScriptType, signature: bytes, signature_index: int, sighash: int):
+
+    signatures = multisig.signatures  # other signatures
+    if len(signatures[signature_index]) > 0:
+        raise ScriptsError('One of the multisig signatures occupies the current signature\'s spot')
+    signatures[signature_index] = signature  # our signature
+
     w = bytearray()
     # starts with OP_FALSE because of an old OP_CHECKMULTISIG bug,
     # which consumes one additional item on the stack
     # see https://bitcoin.org/en/developer-guide#standard-transactions
     w.append(0x00)
-    for s in other_signatures:
+
+    for s in signatures:
         if len(s):
             append_signature(w, s, sighash)
 
-    append_signature(w, current_signature, sighash)
-
     # redeem script
-    redeem_script = script_multisig(pubkeys, m)
+    pubkeys = multisig_get_pubkeys(multisig)
+    redeem_script = script_multisig(pubkeys, multisig.m)
     write_op_push(w, len(redeem_script))
-    write_bytes(w, script_multisig(pubkeys, m))
+    write_bytes(w, redeem_script)
     return w
 
 
diff --git a/src/apps/wallet/sign_tx/signing.py b/src/apps/wallet/sign_tx/signing.py
index 4af12dee0a..bac784595e 100644
--- a/src/apps/wallet/sign_tx/signing.py
+++ b/src/apps/wallet/sign_tx/signing.py
@@ -504,8 +504,9 @@ def input_derive_script(coin: CoinType, i: TxInputType, pubkey: bytes, signature
 
     if i.script_type == InputScriptType.SPENDP2SHWITNESS:  # p2wpkh or p2wsh using p2sh
         if i.multisig:  # p2wsh in p2sh
-            return input_script_p2wsh_in_p2sh(output_script_multisig_p2wsh(multisig_get_pubkeys(i.multisig),
-                                                                           i.multisig.m))
+            pubkeys = multisig_get_pubkeys(i.multisig)
+            script_hash = output_script_multisig_p2wsh(pubkeys, i.multisig.m)
+            return input_script_p2wsh_in_p2sh(script_hash)
         # p2wpkh in p2sh
         return input_script_p2wpkh_in_p2sh(ecdsa_hash_pubkey(pubkey))
 
@@ -514,8 +515,12 @@ def input_derive_script(coin: CoinType, i: TxInputType, pubkey: bytes, signature
 
     # multisig
     elif i.script_type == InputScriptType.SPENDMULTISIG:
-        return input_script_multisig(signature, i.multisig.signatures, multisig_get_pubkeys(i.multisig), i.multisig.m,
-                                     get_hash_type(coin))
+        signature_index = multisig_pubkey_index(i.multisig, pubkey)
+        if signature_index is None:
+            raise SigningError(FailureType.DataError,
+                               'Pubkey not found in multisig script')
+        return input_script_multisig(
+            i.multisig, signature, signature_index, get_hash_type(coin))
     else:
         raise SigningError(FailureType.ProcessError, 'Invalid script type')