Chosen Solution
I have got a galaxy a12 that has had a screen replacement (screen was pulled off a non-working phone) and it keeps glitching out and it shows the boot animation and the lock screen and then the screen goes black and when it comes back it comes up with a load of lines. Any idea why this is happening? I think the phones region is from Russia.
It could be a different screen. the A12 has 3 different screens that will fit but will not work correctly. You need to make the phone it came from is the EXACT same model number.
