From 13715e8020c94111d63a808f9a91e1a1ecaac6a0 Mon Sep 17 00:00:00 2001
From: Salvatore Ingala <6681844+bigspider@users.noreply.github.com>
Date: Mon, 23 Mar 2026 13:57:15 +0100
Subject: [PATCH] Fix incorrect check in cache_unsigned_tx_pieces

`self.tx is not None` is always true because the constructor sets
`self.tx = CTransaction()` when `None` is passed, which causes a
call to `setup_from_tx` also for PSBT version 2, contrarily to the
function's stated intent in the documentation.
---
 hwilib/psbt.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hwilib/psbt.py b/hwilib/psbt.py
index 28b5e1888..ca226d617 100644
--- a/hwilib/psbt.py
+++ b/hwilib/psbt.py
@@ -1047,7 +1047,7 @@ def cache_unsigned_tx_pieces(self) -> None:
         """
         # To make things easier, we split up the global transaction
         # and use the PSBTv2 fields for PSBTv0
-        if self.tx is not None:
+        if self.version == 0:
             self.setup_from_tx(self.tx)
 
     def setup_from_tx(self, tx: CTransaction):