Default [Q] random reboots with janjan 4.4.2 v2.2 rom

I9505 (euro/international, not connected to any carrier)
I used to run samsung's 4.2, it ran fine. later I ran some hacked google 4.3, it ran fine too.

after that I tried 4.4.1, and after many trials and tribulations managed to get it to work, with functional wifi and phone. Not sure if I get LTE, never saw the appropriate letter on the signal bar, but then again I can't vouch for LTE network where I live anyway.

but... started getting random lockups/reboots. typically once or twice a day, when phone is idle. I only notice those as I get a notification from startup manager than boot took NN seconds. twice witnessed this first-hand. once while fiddling with the phone, another time during a call.

screen, button backlight, notification etc all go blank, phone stops responding to any buttons. stays like that for half a minute or a minute. after that responds to voldown-power-home hold force reset and possibly a little later to power button hole power on. if left unattentded boots up after a while too.

a possible hint to what's going on, camera freezes sometimes, when it does other apps, like flashlight, refuse to start claiming that dive is already used.

upgraded to janjan 4.4.2 v2.2, problem still there.

verified that I'm running recommended XXUEMKE modem.

not sure what other flashable parts are recommended. e.g. non-hlos.

can someone who runs 4.4.x on i9505 possible tell me exact versions of all the partitions?
or download said partitions and tell me e.g. md5 hashes thereof?

thanks