I'm would like to know, how can be firmware debugged on Duet 2 Ethernet Board. SAM4E8E chip has JTAG and Serial Wire interfaces, but on Duet 2 board are those port not accessible, because some of their pins are wired somewhere. I'm curious, how debugging was done, when official RepRap Firmware was ported for this board. I don't think, that Duet developer are hyper-inteligent creatures, that can always write code, that works on first time as it should work, so I'm pretty sure, that Duet developers has to have some debugging options. But I wasn't able to find much about debugging.
There is debugPrintf() method implemented, which prints debug message via USB serial interface, but this way I can't print messages right before firmware crash, because this way is somehow asynchronous. It would be really useful, if there was a way, to stepping trough code lide by line, just like JTAG can. Or at least, if there would be some way, to ensure all debug messages are sent before firmware crash.
Thank you for some hints.