iPhone 6 Keeps Restarting? - Fix Error 9 14 40

Blake Feb 17, 2017

More and more people reported that their iPhone stuck in a restart loop. The phone continuously restarts and became totally unusable, the Apple logo appears and disappear, over and over again.


iPhone 6 Keeps Restarting


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


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 the soldering iron , knife, BGA paste flux , rosin , solder wick and PCB cleaner.


7. Connect the NAND flash programmer with the 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 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. (You can read our What Do All These iPhone Error Codes Mean  to learn more)

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 Programmer Mobile Phone Repair Platform Digital Multimeter Soldering Iron Station Hot Air Gun PCB Holder Screw Drivers Tweezers If you want to know more about these tools, you can check out our  online store . The price of each product has displayed, shipping fees as well. If you meet any question during shopping progress, feel free to contact service@rewa.tech . And there are some other repair guides:


Fix cracked iPhone 7 screen ,

Samsung Galaxy S7 edge glass replacement ,

iPhone 7 touch screen not working ,

iPad Air Touch Screen Partially Unresponsive Repair ,

iPhone X Screen Refurbishing – Glass Only Repair ,

iPhone 8 Broken LCD Screen Refurbishing,

iPhone 6 replacement screen ;

iPhone 6 won’t turn on ,

How to fix water damaged iPhone 6 ,

MacBook air memory upgrade .

REWA also provide video tutorials for all visitors, you can learn our repair technology from the video.







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