Hey Guys I got a similar Problem. I changed the damaged Backhousing with a cheap one (China, pre installed Lightning+Power+Louder+Antenna Flexes) of a Iphone 11 and got the same issue, restart after 180sec. In the Paniclog there was the missing sensor Mic2. So I bought a Original Power-Flex from ebay, but this was not the solution. Could the new one also be faulty? Should i also replace the other pre installed flexes? Or could it be the Motherboard?