Chosen Solution
This iPhone 6 was water damaged. I removed all the EMI shields and cleaned up the board. The phone does turn on and everything works but the cellular network. Modem firmware does not show up in Settings>About and *#06# doesn’t return the IMEI. There is a missing part near the baseband chip and I thought it might be the cause. What do you guys think? Can I short the part and see if it works?
This is an inductor, not a filter (ferrite bead). L3204_RF is used within the switching power supply (U_PMICRF). If it is missing, that would impede the production of VREG_SMPS2_1V25 and that explains why (or partly why) the baseband functionality isn’t working. You cannot short it out otherwise the voltage rail will not be produced. Inductors are integral in the design of SMPS. You can read more here: https://en.wikipedia.org/wiki/Buck_conve…
