diff --git a/python/src/trezorlib/stellar.py b/python/src/trezorlib/stellar.py
index c174d4ea6..74e3a0585 100644
--- a/python/src/trezorlib/stellar.py
+++ b/python/src/trezorlib/stellar.py
@@ -207,7 +207,7 @@ def _read_operation(op: "Operation"):
             trusted_account=op.trustor,
             asset_type=asset_type,
             asset_code=op.asset_code,
-            is_authorized=op.authorize.value,
+            is_authorized=bool(op.authorize.value),
         )
     if isinstance(op, AccountMerge):
         return messages.StellarAccountMergeOp(