iPhone 7 Update System error 4014 fault repair

Machine model: iPhone 7
Symptoms: Update System reported error 4014

iPhone 7 Update System error 4014 fault maintenance Figure 1.

Fault analysis:iPhone 7 Update System reported an error of 4014. It is likely that there is a problem with Nand, or it may be a CPU problem, which depends on the progress of Update System.
Maintenance process: check the progress of Update System with computer Update System again. When Update System arrives at Recovery mode, nothing is displayed behind SN, obviously Update System is not recognized.

iPhone 7 Update System error 4014 fault maintenance Figure 2.

Dismantle the main board SMD REWORK STATION, remove Nand, and read it on the test rack. The test found that it could not be read.

iPhone 7 Update System error 4014 fault maintenance Figure 3.

It seems that Nand is damaged. Find a good Nand and install it on the motherboard.Nand can see if it can be identified.

iPhone 7 Update System error 4014 fault maintenance Figure 4.

Update System can identify Nand again.

iPhone 7 Update System error 4014 fault maintenance Figure 5.

Update System can also pass normally.

iPhone 7 Update System error 4014 fault maintenance Figure 6.

The next step is to query SN, WIFI and Bluetooth address codes, and then write them on the test rack again. Back to the motherboard,Update System again, you can activate it.
Update System was activated successfully, the function test was normal, and the maintenance was finished. This fault was no booting caused by Nand damage.