iPhone 6 Keeps Restarting? – Fix Error 9 14 40

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More and more people reported that their iPhone stuck in a restart loop. As we know, the cell phone has been more and more important in our life, we trust our iPhone and they need to work all the time. But When your iPhone keeps restarting and you can't use your iPhone well, it will be very terrible. So what should you do when your iPhone 6 keeps restarting? We'll explain what causes your iPhone 6 to keep restarting and how to fix the restarting iPhone problem.

First, you should know why does your iPhone keep restarting?

Usually, there are two categories of iPhone keep restarting:

  • iPhones that restart intermittently: You can use your iPhone for a while with no problem at all, and then your iPhone suddenly restarts.
  • iPhones stuck in a restart loop: Your iPhone continuously restarts and it’s totally unusable. The Apple logo appears and disappears on the screen, over and over again.

For the first category, you can do the following steps will solve your problem.

1. Back Up Your iPhone

Before we do any troubleshooting at all, make sure your iPhone is backed up. This is a necessary step to protect your personal data.

2. Update Your iPhone’s iOS(if your iOS is the latest version, you don’t need do this step)

iOS updates always contain lots of fixes for software bugs and other problems. Sometimes, a software update fixes the problem that’s causing your iPhone to restart.

3. Reset All Settings and APP

If you installed an app just before your iPhone began restarting, uninstall that app and see if the problem resolves itself. If it's not this reason, you can try reset all setting.

 If the above steps can't solve your problem, your iPhone may fall into the second category. When you have eliminated the possibility a software issue is causing your iPhone to keep restarting and you have checked for hardware issues on the outside of your iPhone. If your iPhone is still restarting, your iPhone probably needs to be repaired. You need to repair your iPhone, there is a video iPhone 6 Keeps Restarting Repair will teach you how to fix it?

This video show you show how to fix iPhone keeps restarting. The iPhone continuously restarts and became totally unusable, the Apple logo appears and disappear, over and over again. Does your phone ever meet this common problem which drives you crazy? Watch our video to get it fixed now!

 The detail steps:

1. Take down the LCD screen assembly

2. Test voltage of the battery with the 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 a soldering iron, knife, BGA paste flux, rosin, solder wick and PCB cleaner.

7. Connect the NAND flash programmer with a computer, transfer the data from the old NAND flash to a new one.

8. New NAND flash chip BGA rebelling.

9. Install the new NAND flash chip to the motherboard.

10. Install the motherboard on 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.


Tools Used:

64 Bit Nand Flash Memory Chip Programmer

Mobile Phone Repair Platform

Digital Multimeter

Electric Soldering Iron

Hot Air Gun

PCB Holder



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