How long you have to heat to be able to open back cover? I do not want to overheat phone.I had the same issue in December - I sent it back to the store I bought it from, and they repaired it, but after a short while it had the same problem again. I ended up repairing it a 2nd time myself.
For me it was the flex cable that stretches from the charging port over the battery to the mainboard - I suspect it overheats or becomes detached or some combination of those two things. I suspect the 'turbo' charger that comes with the phone overheats the battery and damages that cable, but it's only a suspicion. Since I repaired the phone I've been using a quick charge 3 charger instead... not as quick but not too bad either.
This is a repair video for it that I found after I fixed mine... if you wanna try doing it yourself. Not horribly difficult...
You'd need a new flex cable first - I ordered two from SunSky and had it delivered for around 13 Australian dollars altogether. It's been working since I fixed it back in January without any problems.
I didn't have trouble opening my cover as the people at the shop I bought it from who repaired it the first time had already opened it - I didn't have to heat it up at all. I used a guitar pick to re-open it... wasn't difficult.How long you have to heat to be able to open back cover?