Debug message in bootloader


I am trying to modify the bootloader and to debug the bootloader I wanted to add the debug messages. But I am anot able to do this as enabling
#define BOOTLOADER_DEBUG SDU1” in support.cpp file is giving compilation warning.

from the following macro
#define BOOTLOADER_DEV_LIST (BaseChannel *)&SDU1,(BaseChannel *)&SD2,(BaseChannel *)&SD3,(BaseChannel *)&SD7

Please suggest how to enable the debug statement and making this USB port for debugging.

Thank you.


This is a software problem and you probably should ask this on Ardupilot forum.

Also, you should share the full error messages so that we could figure out what the compiler is trying to tell you.