Phone not turning on or Boot loop after flashing Custom ROM (FIX)

Before going further, you may need to check whether you can go to Fastboot or Bootloader (To check just GOOGLE it that how to go to fastboot in your particular device), Recovery (To check just GOOGLE it that how to go to Recovery in your particular device). If you can’t go to recovery don’t give up and try to flash ROM through Bootloader or Fastboot (If available). If you have neither of these available, you have may be hard bricked your device and it can not be fixed. If you have both of these or only Recovery available you can continue reading...

Why your Android phone is not turning on or Boot looping?

There can be several reasons that why your device not turning on or bootlooping, some of are following:

Disclaimer: I am not responsible for bricked devices, Fire, Exploding, etc. YOU are choosing to make these modifications. Your warranty will be void if you tamper with any part of your device.

Reason 1: Flashing an unsupported ROM

Because different Android devices use different hardware, which requires special drivers (e.g. the camera). Installing an incompatible ROM, in the best case, makes components of your device unavailable (they are simply not working). In the worst case, you might "brick" it (it will not even start up).

Fix for Reason 1: First, we will need to know whether your phone is Soft Bricked or Hard Bricked. This can be easily checked by going into recovery or if the device is boot looping or stuck at splash screen, your device is Soft Bricked and if your device is not turning on (Full Blank), your device is Hard Bricked. Hard Bricked cannot be fixed without going to Service Centre or a Mobile Repairing Store. Soft Bricked could be easily fixed by flashing a supported ROM or stock ROM via Recovery or Flashing through Fastboot or Bootloader.

Reason 2: Forgot to wipe Data and Cache

If you've flashed a ROM and your phone won't boot into the home screen or keeps rebooting, it’s probably because you did not wiped the Data and/or Cache. The system is trying to boot into the rom but the leftover data from the last ROM is causing an error which is also responsible for the system to reboot or not boot at all. To understand easily consider this example, Imagine you have eaten a bowl of noodles and there is noodle left in the bowl. After that, Will you eat Ice Cream in the same bowl for dessert?, No. So, the Android System has the same problem that we had in the example.

Fix for Reason 2: To fix this issue you will have to wipe Data and Cache before you flash any ROM in you Android System to avoid this kind of problem.

If you can’t solve this issue

This is less likely, but it's a problem if you have run into on occasion: Sometimes your SD card just gets corrupted, which makes the above methods useless. So, if you can, just Backup your SD Card and format it. After that, flash any compatible ROM or try the above steps again.