iPhone 7 The damaged charging chip caused the phone Stuck on Apple logo to restart and repair

Machine model: iPhone 7
Fault symptom: the mobile phone Stuck on Apple logo restarts
Fault analysis: There are several possibilities for irregular restart that often cause problems. First, battery VCC is abnormal; Second, the BUCK circuit VCC of CPU is abnormal; Third,VCC works unstable.
Maintenance process: the mobile phone is online, and i4 is turned on, without looking at the battery information.

iPhone 7 The damaged charging chip causes the phone Stuck on Apple logo to restart and repair Figure 1.

schematic shows that the charging management chip U2101 will transmit the battery information to the CPU. If there is no battery data, it is mostly that there is something wrong with this part, so replace U2101 directly.

iPhone 7 The damaged charging chip causes the phone Stuck on Apple logo to restart and repair Figure 2.

After the replacement, the machine is turned on, and the battery times and battery life have been displayed. After brushing Keeps Shaking, everything is normal, and there is no restart phenomenon, and the repair is completed.