fix(legacy): Fix Decred transaction weight calculation.

legacy/firmware/transaction.c

@@ -1132,6 +1132,10 @@ uint32_t tx_output_weight(const CoinInfo *coin, const TxOutputType *txoutput) {
 uint32_t tx_decred_witness_weight(const TxInputType *txinput) {
   uint32_t input_script_size =
       tx_input_script_size(txinput, txinput->script_type);
+  if (txinput->script_type == InputScriptType_SPENDMULTISIG) {
+    // Decred fixed the the OP_FALSE bug in multisig.
+    input_script_size -= 1;  // Subtract one OP_FALSE byte.
+  }
   uint32_t size = TXSIZE_DECRED_WITNESS + ser_length_size(input_script_size) +
                   input_script_size;
 

tests/ui_tests/fixtures.json

@@ -15,7 +15,7 @@
 "T1_bitcoin-test_bgold.py::test_send_p2sh_witness_change": "9fd0d868aa3d4b9ea4066b1124f51d469edcc57a9a234bc5dc48eef63f55ce6b",
 "T1_bitcoin-test_dash.py::test_send_dash": "f82f04808cbd87e88e268e923c35c05217ecde6c1aea27d114b44262cb813cd7",
 "T1_bitcoin-test_dash.py::test_send_dash_dip2_input": "e219fbf1899be32e6097ad57ea5fe204c347cc710d0659c7d4972b5253e63b25",
-"T1_bitcoin-test_decred.py::test_decred_multisig_change": "753e37c526434f2ed71ace99c15c610591600d8384e8303815e60376516a2bac",
+"T1_bitcoin-test_decred.py::test_decred_multisig_change": "e3e6bdcad7c8deee8c91c8cedff34668255bdd93bf1cfb4f4f46060a356cf494",
 "T1_bitcoin-test_decred.py::test_send_decred": "ef4422f3cff7add5192c753a5c5640dad06b82936bf31fd94baaebfae2280aac",
 "T1_bitcoin-test_decred.py::test_send_decred_change": "42814de3a9199b4b683bcde8595d7987b48cfeb609bd63926dd66abc7e5611fc",
 "T1_bitcoin-test_descriptors.py::test_descriptors[Bitcoin-0-InputScriptType.SPENDADDRESS-pkh([5-7a80e3db": "9b30c98b35338d933fe992e4a47fb259a54f0f6f204610f63c6e6cbff427dbb9",