iPhone6 Plus brush failure repair

Model: iPhone6 Plus
Fault symptom:Update System failed and reported 40 errors
When the mobile phone is used for expansion, the bottom of UMT manufacturer’s board, the expansion caused no booting and Update System to report an error of 40. The customer stated that it could be repaired if it could be repaired, but not Move Board ,move the main chips to another motherboard.

iPhone6 Plus brush failure repair figure 1.
Fault analysis:
After the capacity expansion,no booting and Update System reported an error of 40. This kind of failure is usually caused by the communication between CPU and Nand, and Nand can not be identified. This kind of failure can be caused by the damage of the line between them or Nand itself.
Maintenance process:
Connect the mobile phone computer Update System to see if Nand can be recognized. In the interface from Update System to Update System,SN was blank, and Nand was obviously not recognized.

iPhone6 Plus brush failure repair figure 2.

Take the phone apart and observe it under the microscope. We can see that Capacitor around Nand has dropped a lot.

iPhone6 Plus brush failure repair figure 3.

Remove Nand, hit Nand U0604 Nand to diode value, and found that everything was normal. Take Nand to the test rack to read, and found that Nand was damaged, and reading failed.

iPhone6 Plus brush failure repair figure 4.

iPhone6 Plus brush failure repair figure 5.

Back to the customer’s original machine 16GB Nand, soldered back to the main board,Update System can identify Nand as a progress bar.

iPhone6 Plus brush failure repair figure 6.

Maintenance result:
Update System passed. It seems that the expanded Nand is broken, which caused the mobile phone Update System to report an error of 40. Finally, the customer was replaced with a 64GB Nand, and the Update System around Nand was replenished. This is the end of the maintenance.