iPhone boot loop problem is often seen on iPhone SE2, iPhone X and iPhone 11 series. Analytic information on the problematic iPhone can be found in a panic log file. Information in the red circle shows the cause of this problem. In this case, it was the missing thermalmonitord sensor. This thermalmonitord sensor resides on mic1, which was on the charging port flex.
What caused this problem?
iOS is designed to manage Apple handsets efficiently. When it detects something wrong, missing or problematic, it carries out an operation. Reboot is one of the operations.
Possible causes of 3 minutes (180s) boot loop
Many problems can cause an iPhone enter 3-minute boot loop. Damaged charging ports, power/volume flex, or open circuitry on the motherboard that prevent the CPU accessing thermalmonitord etc.
Solutions to this infinite boot loop issue vary depending on what the causes are.
The first thing is to spot where the problem is. Then replace the faulty charging port or other accessories. If it’s not the accessories problem, you need to consider repairs to the faulty motherboard. To repair the motherboard, you need to spot the problem according to the panic info.
Images below show the repair we did to the thermalmonitord on mic1 missing. There are different approaches for different causes.
Check this link out for more 180s boot loop info: