Just cataloguing an enhancement request from FOSDEM 2003:

Debugging support commands in RedBoot, i.e. the ability, from the RedBoot
prompt, to do things like exitting back to the ROM monitor prompt (with Ctrl-c,
a physical button on a board, soft magic in the application or whatever),
breakpoints, stepping, etc. I know Cygmon used to have these (plus a simple
non-GPL disassembler for x86 and some other arch), and of course "competing" ROM
monitors also do.