LG G4 Bootloop Repair: Memory & Cold Solder Issues, Overheating, Ball Placement, Poland Services

Some time ago my LG G4 started to reset. After checking it turned out that it is a bootloop and LG has washed out for complaints.
Since there is no access to hot air, I dismissed it to a cell phone service. Unfortunately, gentlemen were warming so that the phone no longer turns on. According to the specs, memory is to blame (I doubt it), but it seems to me that they were heating up this bone.
I suspect either overheating the wrong bone or damage the balls.
Being in Poland on vacation I went to several GSM factories, in which it was stated that they do not put balls, so I am looking for a bet that could try to save the disc, because I really like this phone.
Is the bootloop on this phone really caused only by cold solders or total chip damage? I am asking because I am wondering how permanent the heating repair is
I know that this is not the right place, but I do not know of any sensible plants in Poland that deal with such things, which is why I will be very grateful for the information about who does it.

Damage to memory can produce such symptoms.
If you want you can order a repair in the department GSMBazar
The best solution is to replace the entire disc.

Thank you.
"spece" in the UK emmc bone warmed up and from what they write in the net is supposedly wine is borne by the processor so it is possible that both are damaged
I looked at new discs, but they are more expensive than the phone and unfortunately no one can guarantee that the new one will not fry after a while ... That's why I wanted to try new balls and if not then you need to look for a new phone.