Stumped By iPhone 6 Reboot Loop
 

Guys, I'm running into a problem with my iPhone and it seems like I've tried everything to no avail. Would really appreciate more troubleshooting ideas. I tried using the search function but I may have missed a similar thread.

Phone Information

• Model: iPhone 6 (A1549) 64GB
• Carrier: Verizon
• Operating System: Latest iOS (no jailbreak)
• Age: 2 years

Problem Symptoms

• Press power button, Apple logo appears for a few seconds then screen goes black and the process restarts.
• If left alone, process will repeat for about 10 minutes before the cycle breaks and the screen stays dimly backlit for hours.
• After a few hours the dimly backlit screen will drain the battery and phone will shut off.
• Pressing power button now will show the dead battery screen indicating to plug phone in to recharge.
• Once plugged in, phone will recharge and boot back up to start the whole thing over again.

Problem Origin

• I broke screen a few weeks ago and replaced the LCD/Digitizer with a new one from Amazon.
• New screen seemed to be working perfectly fine for weeks.
• I noticed battery was draining faster after new screen installation and proximity sensor stopped working.
• Suspecting damage to the front camera assembly while switching it to new screen I ordered a new assembly from Amazon.
  
• Phone was working fine until this point; This is what I did the day my phone died:
• Turned phone off.
• Disconnected battery connecter.
• Disconnected screen.
• Switched out front camera assembly.
• Reversed process and powered up.
• Phone has been stuck in this reboot cycle since then.

Troubleshooting

• First thing I tried was simply going back with old camera assembly. That changed nothing; phone will power on, show log for a few seconds then restart.
• Tried starting with the camera assembly completely disconnected and nothing changed.
• Tried starting with nothing but LCD screen connected (no digitizer, no front assembly, no home button) and nothing changed.
• Disconnected battery and tried starting while plugged in to charger. Phone got stuck in reboot cycle again as if nothing changed with battery out.
• Let battery completely die until phone indicating that it needs to be plugged in to charge. Then I left it on the charger overnight. It recharged, powered back up and loop started again.
• Replaced battery with a new battery and nothing changed. Tried a third battery, nothing changed.
• Took phone apart down to logic board to see if I had accidentally disconnected something and brushed all connectors before I reassembled. No change.
• Updated iTunes then plugged in my phone to see if I can get a firmware update. As the process starts phone reboots and gets stuck in loop again. iTunes says I should do a restore.
• Tried manual firmware update by holding shift while clicking "Update" in iTunes and used the latest firmware file which I had already downloaded. As soon as update process starts phone reboots and gets stuck in loop again.
• Started restore process in iTunes acknowledging that it will wipe all my data. As soon as restore process starts phone reboots and gets stuck in loop again.
• I can put phone in DFU mode and then kick it out of DFU mode using Tenoshare's ReiBoot. I have not tried using ReiBoot pro which claims it can fix this issue but reviews looked shady.
• Swallowed pride and took phone in to a repair shop (not Apple Store). They said they have no new ideas beyond what I tried.

I am completely out of ideas. If you have any suggestions that may save my phone I would love to hear them; will ship beer for an idea that works!

You need to check if you didnt damage the pcb while changing the lcd. Also you will have to check screw holes with microscope to see if you didnt make any screw damage to board layers.

hi

you problem seems to be charging ic alias U2 ( for IPH.6 <U1700>) and / or Q1701 ..replace U1700 and test starting with battery to zero charge.

Thanks, Orx. I've been doing some reading to make sure I understand what you're saying. Can the Charging IC be the cause even through the battery seems to discharge and charge normally? I can leave the phone stuck in restart loop until the battery dies and phone indicates that I need to plug in. If I plug in for 10-15 minutes the phone will restart.

hi

usb / charging IC , in your case after replace dock and battery is the successive step .
Battery with quick discharge e request of to connect power charge can to be the symptom.

I already replaced the battery. Are you suggesting I replace the lightning connector next?

Here are 3 options to fix iPhone Stuck in Boot Loop:

1. Checking the battery connector
2. Putting your iPhone into Recovery Mode
3. Upgrade and restore your iPhone with iTunes.
4. Using iMyFone iOS System Recovery.

1- change lcd
2- change U2 IC
3- new battery
Disconnect ( charger dock - all cameras cables )
Turn on

I hope the BCP is fine

iPhone Stuck in Boot Loop
 

Hope that it will be helpful for you!

Try to change tristar (u1700) it is not a charger itself, it is usb controller (and only it)

i have same problem on a device too

you should try the logic board in known good housing with known good battery etc , if problem persists then you have a logic board problem , check the board for visible damage under microscope , the phone is boot looping so is not getting the message to turn on tristar is the usual culprit but can be anything on that line , so change tristar which is quite a simple process then take it from there good luck

This symptoms they refer to error 9/4013/4014

Possible i2c communication problem (CPU to NAND), or NAND corrupt.

The reasons, like wrong update, device jailbreak and battery problem, can cause this iOS issue. If you want to fix iPhone stuck in boot loop, you might as well simply force restart, use iTunes, or repair with iOS system recovery or something else, like Volumn Up trick, etc. Hope you can get out of this trouble soon.

Here are different solutions to fix iPhone stuck in boot loop issue.

If these solutions are not workable for you, try iOS System Recovery program.