Debug log to a file

[BobanSpasic]

Hi folks

is there any possibility to get a debug log as a file?
Namely, I am trying to get MiniDexed to run on Zero 2W in USB Gadget mode. I have an HDMI monitor (7" touch), but it does not show anything (it goes to standby) so I have no clue why it isn't booting. It would probably help if I could get some debug log in a file.

[rsta2]

There is no standard way for writing a log file, but with some small source code it is possible. See the archive attached. It contains two files fatfslogfile.h and fatfslogfile.cpp, which must be copied into the src/ directory of MiniDexed. Then apply the patch logfile.patch from MiniDexed root with
patch -p1 < logfile.patch and rebuild MiniDexed. I did not test it with MiniDexed, so problems may happen.

It should open a file minidexed.log on the SD card and writes eventual log events into it. Please note that the file may remain open, because there is nothing (despite a hard system error), which can trigger the close. You may have to run a file system check (e.g. fsck.vfat) for the SD card after running it. That's not perfect, but for a quick test, it should be OK.

There is some chance, that your problem happens, because the via USB supplied power is not sufficient. In this case this tool will not help, because the system does not run at all.

[rsta2]

Oops, I forgot the archive:

minidexed-logfile.zip

[BobanSpasic]

Did some further tests here probonopd/MiniDexed#568 (comment)
Raspbian Lite (console only) 32-bit boots fine. LibreELEC stops with an error.
I'll see if someone could build the version with logging for me because I have no clue how to do it myself.