iPhone 6 Plus logic chip flying to solve boot white apples restart repair

iPhone 6 Plus logic chip flying to solve boot white apples restart repair

Machine model: iPhone 6 Plus
Malfunction: Hang Logo(white apple)restarts after startup.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 1.

Failure analysis: The chip failures that will cause Hang Logo(white apple)to restart include: CPU, Nand, logic EEPROM, Baseband, etc. It seems that the working conditions of these chips should be checked first.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 2.

Maintenance process: First, measure the ground diode value and VCC of CPU and find that they are all normal. Then, measure the working conditions of Nand and find that they are all normal.

When the logic EEPROM is measured, it is found that one of the buses (AP_TO_EEPROM_I2C) connecting the logic EEPROM and the CPU,EEPROM, is more than 600 to the ground diode value, which should normally be 400 CLK, which seems to be disconnected or CPU pin Open.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 3.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 4.

Because there is a problem with only one bus, I choose to dig the CPU for Jump wire maintenance. After all, it takes more time and risks to redo the CPU. Determine the scope of excavation by searching data, and install new blades to prepare for work.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 5.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 6.

We’ve dug through the upper layer and started to dig the lower layer. Here comes the key position. Be extra careful.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 7.

Dig out GND on the first floor, exposing the signal traces on the second floor.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 8.

After carefully digging out the wires, paint the extra places with Solder Mask, and then tin the bus to start Jump wire.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 9.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 10.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 11.

And the other end is connected to the pull-up resistor of AP_TO_EEPROM_I2C_SCL.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 12.

After the measurement, it was found that diode value returned to normal, and then the test was started.

iPhone 6 Plus logic chip flying to solve boot white apples restart repair Figure 13.

Maintenance result: the boot display is normal, and the system can be booted, indicating that the fault has been solved and the maintenance is over.