Revert "fix(core/thp): disable THP ACK piggybacking as a workaround for #6506"

This reverts commit 586df8a.

Author: romanz

core/.changelog.d/6202.added

@@ -0,0 +1 @@
+Support receive-side THP ACK piggybacking.

core/src/trezor/wire/thp/__init__.py

@@ -210,8 +210,7 @@ def _get_device_properties(iface: WireInterface) -> ThpDeviceProperties:
         internal_model=utils.INTERNAL_MODEL,
         model_variant=model_variant,
         protocol_version_major=2,
-        # TODO: re-enable THP ACK piggybacking after #6506 is fixed
-        protocol_version_minor=0,
+        protocol_version_minor=1,
     )
 
 

core/src/trezor/wire/thp/received_message_handler.py

@@ -106,11 +106,10 @@ async def _handle_state_handshake(
     def _handshake_callback(ctrl_byte: int) -> bool:
         success = control_byte.is_handshake_init_req(ctrl_byte)
 
-        # TODO: re-enable THP ACK piggybacking after #6506 is fixed
-        # if success and control_byte.get_ack_bit(ctrl_byte) == 1:
-        #     # Newer Suite versions will send `handshake_init_req` with a non-zero ACK bit.
-        #     # The device should not use ACK piggybacking with older Suite versions.
-        #     ABP.allow_ack_piggybacking(ctx.channel_cache)
+        if success and control_byte.get_ack_bit(ctrl_byte) == 1:
+            # Newer Suite versions will send `handshake_init_req` with a non-zero ACK bit.
+            # The device should not use ACK piggybacking with older Suite versions.
+            ABP.allow_ack_piggybacking(ctx.channel_cache)
 
         if __debug__:
             ctx._log(