Chosen Solution
I recently changed my battery. After that everything seemed to worked just fine for a couple of hours. But when a was trying to calibrate the battery, doing a fully discharge, and then charge it, never turned on and began rebooting loop with a red screen that shows up sometimes. I just have spend all my day trying to fix it with out solution. First I tried to do a hard restart;I changed display, (my old display works fine);I took out from display the proximity camera flex cable;Using the original battery. I just don’t know what else can be. Please help me
Try turning on the phone with the front camera unplugged as that may cause red screen of death boot loop. Another thing to note is the two screw holes below the screen connector area on the logic board. If longer screws are put into that hole or overtightened the phone may have long screw damage meaning the circuit traces in that screw hole have been damaged which can cause this issue too. This may sometimes be hard to spot without looking into those screw holes under a microscope. In most causes it may require micro-soldering / board-level repair work done to it to get it working again. Sometimes even a restore / update via iTunes / 3UTools can fix it too.
This is what you need to do.
- Plug in the charging cable
- backup your data on icloud
- change the front camera flex
- restore the phone via itunes
- setup the phone using icloud backup and your phone should be working back to normal
Take it to an Apple Authorized Service Provider. They can run diagnostics on it to determine why it loops. Find an Apple Authorized Service Provider at https://locate.apple.com/pr/en/
