I've tried flashing android 4.4 (but this creates the soft-brick looping while starting android).
I've tried factory reset,
I've tried hard reset
And I've tried the manual resets by flashing 4.2.2 back on.
In all combinations
What can be done, and how can I start using my mobile phone as a PHONE again? Anything but asking for a warranty (as I sadly void It when I had to downgrade from 4.3 to 4.2 to fix a bug introduced in 4.3 that prevented deep sleep)