Hi giulio.bonciani1,
What’s the Jetpack version in use?
Do you mean the debug UART not present on your custom carrier board?
You can refer to Custom carrier board debugging/not booting - #14 by KevinFFF for how we redirect the log to other UART interface which has been verified with JP5.
What’s the UART2 you mean?
Do you mean uarte@3140000?
You can also refer to Jetson/L4T/peripheral/ - eLinux.org for the UART mapping.