Akash

That is Nand issues,Most of the cases you have to reprogram Nand with removing from logic board and reprogram with programmer.

First change the battery and check.

you have to update your firmware,some third party application causes that issues that can`t be fix with hard reset any more. 1- See the which Binary on the phone by download or odin mode. 2- Download the compatible firmware. 3- Backup important data before doing that operation. 4 - Possible remove google account before doing that upgrading via Odin,If you know your id ,pass no problem.

Must have home button issues because Home button also needs to go on DFU mode.Here i put some ideas to non technical person too. Possible chances. 1- Clean the dock connector with toothprik. 2- Disconnect the battery press home and connect battery and insert cable. 3- if you do the following steps and even same that must be the problem of triaster for that you have to need microsoldering skills.

First see the battery information status via 3utool that is present or not.If the battery status not showing that might be the possible region. 1- Faulty battery 2-Battery SWI problem. 3- Battery connector SWI pin broken that causes the bad contact . Sometime restart or battery percentage jumping problem cause that issues.If all are fine in condition you need extra hardware skills.This videos helps you in that cases in Vast level for problem solving.

Flashing or upgrade phone to latest version,Backup important data before doing that operation.

While replacing battery not any problem appear.There is possible reason for that. 1-While open screen might be Home button flex tear. 2-Home button flex connector might be broken pin or not connected properly. 3-Long screw over battery covering metal frame may cause issues. See this on your phone clearly that you got the solution.

First detach the camera flex and back camera connector from logic board and check.

Better put the phone in forced DFU mode and restore via iTunes then see error that makes you to forward to the solution.If any errors seen by this you can solved after seeing errors.

Here you can get the solution. Touchscreen doesn't work after bent frame On the cases is face id disable that the mistake by making with the Apple care technician while change LCD.