you could use the "boot media selector", and add a switch outside your setup, so that your remote hand can access it
Then, SDCard could be used as an emergency boot
So after a gruelling 10 hours drive... I have fixed the Odroid, I checked the log files before doing anything else and nothing came up as bad.
However, I had to re-install the OS, so I picked the 18.04 LTS minimal install image.
I have to re-install all the softwares and tweaks.....
I have a backup of everything, so it's not a big deal to start from a fresh OS install, Hope to have everything done by Saturday as I'm driving back on Sunday.
I'd suggest to make another SD card ready. So if anything goes wrong like this in the future, you can ask your relatives to simply swap the SD card instead of driving all the way to fix it.
Yes going to look into that, have a spare SD card ready to boot, installed, I'll install the switch... I don't have time to do this now, I'll do it in December where I will have more than enough time.