I have an old Blade Vantage 839 by ZTE.
Had a loose charging port, now resoldered but that is another question.
Even before the loose charging connector I had a problem where the phone would shut off and not be able to reboot.
Occasionally I can get it going by holding power and Vol+ until I get to a recovery screen and have done numerous factory resets on the phone.
I can now determine that sometimes i can either restart or power off/on without issue but when I do those steps and do not get the vibration indicator, I am assured that the phone won't start normally.
Is this software related and if so, why wouldn't factory reset normalize the condition?
Or is it hardware. If it takes forever to restart with the Vol+ and power keys, I wrap the phone in a plastic bag and put it in the freezer for 10 minutes or so and then it responds almost immediately to the vol+/power button combination which to me might indicate a faulty solder joint (expansion/contraction) or defect in the SOC. Weird huh?
Please redirect this question to another forum if this is incorrectly placed.
Looking for suggestions.