Sorry for not posting "the rest" but I forgot what it was. Today I had batterry/charging bug I suppose. I couldn't boot my device for long time after crash or emergency shutdown. It succeeded without reflash after long time of retries. The reason why I think it is related with batterry state is the batterry was almost empty at the shutdown or another problem forced my device to shutdown.

I want also to remind old known bug I suppose - in kernel power with multiboot implementation (read it as - not direct booting only kernel otherwise) it fails to boot properly into system while charger is connected - it seems to lock at ACT-DEAD state despite trying to leave it in a way which worked previously. I don't know if it is the same bug as one from ages but rarely occuring or it was new since Kp51 - but I feel forced to remind that - even if user resolution/workaround is trivial - just to disconnect charger, boot up until desktop shown and reconnect it. I hope you would find some time to adress that.

PS: the time it failed to boot was too long for the time it having too low batterry to do the manuever, and I also had the fbcon log with error which I couldn't catch long enough to know what were written, but long enough to see there was at least one then.

EDIT: it seems reseting the device by pulling out batterry for 30 seconds were neccessary to recover non-booting problem but not enough anyway.

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it seems from the behaviour that kp51 after "full" batterry and wallcharger present tries to overcharge the batterry by mistake but it may be wrong device Charging Reporting behaviour under kp51.