Chosen Solution
Hello, my iPhone 5s shows searching after booting up and after 30 seconds it says no service or sometimes Cellular update failed error. I checked the about page in Settings-General and it does not show modem firmware but it shows IMEI. When I go to the phone app and dial *#06# just nothing happens. I remembered that my phone dropped in water like 1 month ago and nothing happened, but after 3 weeks I saw this error. When no service error started to appear, my phone sometimes was able to make or receive calls. Any suggestions should be appreciated! EDIT: I am using this iPhone as an iPod touch now and recently I noticed that every time I boot the device up it shows that Cellular Update Failed error even tho I do not have SIM card installed.
Very bad sign. so Modem Firmware is located on BB_CPU and if you are not getting the firmware its a few of the following that can affect this BB_PMU is not working right therefore you may not be getting voltage to power the BB_CPUThere is a issue with WTR and it is messing with the voltages of PMUBB_CPU needs reballed due to corrosionBB_CPU has a internal short Either way this is a Motherboard that will need a Microsoldering Tech to repair.
