More and more people reported that their iPhone stuck in a restart loop. The phone continuously restarts and became totally unusable, the Apple logo appear and disappear, over and over again.
Does your phone ever meet this common problem which drives you crazy? Now read our post to get some practical tips to fix this issue by motherboard repairing.
1. Take down the LCD screen assembly
2. Test voltage of the battery with digital multimeter. Battery voltage is 4.21V, battery test signal voltage is 2.02V. The battery is normal, so we install the LCD screen assembly to check other malfunctions.
3. Failure detection: connect the phone to computer, it could not be restored by iTunes, an unknown error occurred (9), so that we can draw a conclusion that NAND flash or CPU is cracked.
4. Detach the motherboard from the phone, and fix it on PCB holder.
5. Remove the NAND flash chip from motherboard carefully.
6. Clean the bonding pad with solder iron, knife, BGA paste flux, rosin, solder wick and PCB cleaner.
7. Connect the NAND flash programmer with computer, transfer the data from the old NAND flash to a new one.
8. New NAND flash chip BGA reballing.
9. Install the new NAND flash chip to the motherboard.
10. Install the motherboard to the phone.
11. Connect the phone to computer, it can be restored by iTunes successfully.
12. Test if it works well.
1.Prepare a new 64GB NAND flash memory chip.
2.Error 21, 9, 2009, 4005, 14, 40 indicate NAND flash or CPU malfunction.
3.You may need to repair the CPU if the phone still keeps restarting after the NAND flash chip is replaced.