diff --git a/core/src/apps/bitcoin/sign_tx/approvers.py b/core/src/apps/bitcoin/sign_tx/approvers.py
index a65db4a8e9..639a692750 100644
--- a/core/src/apps/bitcoin/sign_tx/approvers.py
+++ b/core/src/apps/bitcoin/sign_tx/approvers.py
@@ -118,6 +118,7 @@ class Approver:
         self,
         txo: TxOutput,
         script_pubkey: bytes,
+        index: int | None = None,
         orig_txo: TxOutput | None = None,
     ) -> None:
         await self._add_output(txo, script_pubkey)
@@ -184,11 +185,12 @@ class BasicApprover(Approver):
         self,
         txo: TxOutput,
         script_pubkey: bytes,
+        index: int | None = None,
         orig_txo: TxOutput | None = None,
     ) -> None:
         from trezor.enums import OutputScriptType
 
-        await super().add_external_output(txo, script_pubkey, orig_txo)
+        await super().add_external_output(txo, script_pubkey, index, orig_txo)
 
         if orig_txo:
             if txo.amount < orig_txo.amount:
diff --git a/core/src/apps/bitcoin/sign_tx/bitcoin.py b/core/src/apps/bitcoin/sign_tx/bitcoin.py
index 451ac48d38..0474d3c548 100644
--- a/core/src/apps/bitcoin/sign_tx/bitcoin.py
+++ b/core/src/apps/bitcoin/sign_tx/bitcoin.py
@@ -223,7 +223,7 @@ class Bitcoin:
             orig_txo: TxOutput | None = None
             if txo.orig_hash:
                 orig_txo = await self.get_original_output(txo, script_pubkey)
-            await self.approve_output(txo, script_pubkey, orig_txo)
+            await self.approve_output(txo, script_pubkey, orig_txo, i)
 
         # Finalize original outputs.
         for orig in self.orig_txs:
@@ -507,6 +507,7 @@ class Bitcoin:
         txo: TxOutput,
         script_pubkey: bytes,
         orig_txo: TxOutput | None,
+        index: int | None,
     ) -> None:
         payment_req_index = txo.payment_req_index  # local_cache_attribute
         approver = self.approver  # local_cache_attribute
@@ -525,7 +526,7 @@ class Bitcoin:
             # Output is change and does not need approval.
             await approver.add_change_output(txo, script_pubkey)
         else:
-            await approver.add_external_output(txo, script_pubkey, orig_txo)
+            await approver.add_external_output(txo, script_pubkey, index, orig_txo)
 
         self.tx_info.add_output(txo, script_pubkey)
 
diff --git a/core/src/apps/bitcoin/sign_tx/decred.py b/core/src/apps/bitcoin/sign_tx/decred.py
index fd39159038..2b37524e8c 100644
--- a/core/src/apps/bitcoin/sign_tx/decred.py
+++ b/core/src/apps/bitcoin/sign_tx/decred.py
@@ -99,7 +99,9 @@ class DecredApprover(BasicApprover):
     ) -> None:
         # NOTE: The following calls Approver.add_external_output(), not BasicApprover.add_external_output().
         # This is needed to skip calling helpers.confirm_output(), which is what BasicApprover would do.
-        await super(BasicApprover, self).add_external_output(txo, script_pubkey, None)
+        await super(BasicApprover, self).add_external_output(
+            txo, script_pubkey, None, None
+        )
         await helpers.confirm_decred_sstx_submission(txo, self.coin, self.amount_unit)
 
 
@@ -206,8 +208,9 @@ class Decred(Bitcoin):
         txo: TxOutput,
         script_pubkey: bytes,
         orig_txo: TxOutput | None,
+        index: int | None,
     ) -> None:
-        await super().approve_output(txo, script_pubkey, orig_txo)
+        await super().approve_output(txo, script_pubkey, orig_txo, index)
         if self.serialize:
             self.write_tx_output(self.serialized_tx, txo, script_pubkey)