Samsung galaxy s4 wont turn on after the white logo, happening since plugged into portable charger

[AC Question]

So my Samsung galaxy s4 turns on until the point of the second white logo which keeps flashing but will not go further than that. It keeps flashing at that for hours and the phone over heats a lot.
This has happened ever since I plugged it to a portable charger however I have also replaced the battery but that doesn't help either.
I have gone into recovery mode and also tried wipe cache partition but that did not help either.

I do not want to factory reset at all because I have a lot of important things in my phone which are not backed up either cuz I just got back from a trip.

Please help!! I just need to start it once so I can back everything up to use on my new nexus 6.

 

[B. Diddy]

Welcome to Android Central! The only other thing I can suggest is removing the SD card, if present, since a corrupt card can cause various issues. Removing the SIM won't hurt, either. If the problem persists, then it's probably either corrupted firmware or a hardware problem. Corrupted firmware would require firmware reinstallation, which would wipe the phone. Hardware failure would probably also lead to data loss, especially if they had to replace the motherboard. Sorry!