Custom FC with faulty USB

Hello guys,
I recently designed a custom FC based on Pixracer, but I have some trouble with USB, I have ordered a
“fixed” version of the board, but in the mean time, I want to try if I can use the “buggy” version. The microcontroller and IMU seem to work, so I want to enable the telemetry port on the FC to connect to mission planner, so far I have tried to add these line to the hwdef.dat, but no mavlink data, even heartbeat, I don’t know if this is enough or I have messed up something.

define DEFAULT_SERIAL1_PROTOCOL SerialProtocol_MAVLink2
define DEFAULT_SERIAL1_BAUD 115200

the stdout though UART is still working, so I think the board is probably working. I really appreciate any advice, since I am really new to this. Thank in advance :blush: