Some custom boards cannot boot up when UART2 is not connected to the UART dongle. We guess the noise at the RX pin stops the booting process in the bootloader. We experiment that add a pull-up resistor at the RX pin can boot up the system. However, the board is under MP and we cannot modify the circuitry. We try to disable uart2 in the u-boot dts by setting it to disabled but find no use. We can still see the u-boot content at the console during power on. Could someone advise how to disable the UART2 RX pin at u-boot, or even SPL? Or I am going to a wrong direction?
Thanks a lot!
