Back to my D-link DGS-1210-16 issue:
I booted it up, flashed today's snapshot and tried to reboot again.
It still ends up being stuck and only disconnecting power allows it to boot again.
Then I tried to change the minimum frequency to see if there is any difference, but for some reason it told, me, that it has no permission to /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq
I fear, that sth. in my switch might be bricked.
This is the serial console output during these attempts: https://haste.tchncs.de/uwezutohah.yaml
Maybe someone has an idea what can be done to bring back normal functionality with working reboot.