オリジナル投稿者： Minho ,
The missing IC is U_LB_SW and it is part of the Low Band circuitry. IMHO, this is not a required IC and should not impede the phone from booting. If you want to replace it, you can either scavenge it from a donor board or order one on [https://www.aliexpress.com/wholesale?catId=0&initiative_id=&SearchText=iPhone+6+U_LB_SW|Aliexpress]. Daniel makes a good suggestion and if that isn’t the issue, the you need to start probing the circuitry to see if there any shorts. Start with VCC_MAIN, BATT_VCC and then move onto the PMIC outputs.