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Apple's top-of-the-line smartphone for 2020. Announced on October 13th and released November 13th, the iPhone 12 Pro Max sports a 6.7" OLED display, a triple rear camera system with LiDAR, and 5G connectivity. Successor to the iPhone 11 Pro Max.

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iPhone 12 pro max rebooting issue

I was made aware of this issue after repair so have no idea if this was happening before parts were replaced.

Replaced screen, battery (BMS was transferred), back glass, rear camera unit.

Lots of variables here but they are all high quality parts, camera being genuine

Now when using the phone there isn't an issue but when its put on charge every couple of minutes (random), the phone will shut off and reboot.

I am quite new to panic reports but my first suspicion was the charging port or battery. iDevice panic log shows NAND or I2C3 as the issue.

However after analysing the log it seems to me that this is the screen? A timeout for display device eeprom?

Maybe after reprogramming true tone it got damaged in some way? Or just a faulty unit?

All I wanted to ask if anyone has had a similar issue or is able to decipher what the issue is from the panic log. I believe @flannelist is the expert but any help will be greatly appreciated!

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Wow, I'm in the EXACT same boat as you, and I've spent the last week trying to figure it out. I'm at the end of my tether as I've tried a different battery, display, charging flex, and power button flex with no luck. I've also disconnected the front and rear cameras, and faceid dot projector to rule them out...but STILL the phone reboots with an I2C3 display-eeprom error.

The history of my customer's iPhone 12 Pro Max was that it was bent on the battery side from a heavy gym weight. The phone was working fine however the display was badly damaged. Amazingly the back glass was undamaged despite being very bent. I replaced the housing with an original pull frame (came with a battery, charging flex, antennas, power flex). I used a V1S to reprogram a new FX5 Soft OLED screen for truetone and I thought I was done! Turns out the customer complained of a bootlooping issue only when charging it.

Now, I've gone back to the flex cables and battery from the original phone but the issues persist. I have also resorted to replacing the display FPC incase it was a bad connection. Still no joy

Tom, what brand screen are you using?

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Thanks for sharing! And I have good news as there seems to be a link here. Although this phone doesn't seem to have been bent I too have used an FX5 soft OLED panel and reprogrammed with V1SE. I didnt notice any problems at first but when the phone was on charge one time I kept hearing it boot into IOS which I found weird. I assumed this was just that the charge port was getting disconnected. With some further digging it seems to have lead to this that I have described. I did briefly try the genuine screen which seems to stop the restarting.

Although another problem I have is the phone will not keep connection for long with an iTunes software flash and fails. Almost like the NAND just refuses or is damaged?

Another issue I've noticed is that the camera app freezes and doesn't give option of 0.5x. I will do further testing tomorrow with removing and replacing parts but 12 pro maxes have been a nightmare of the issues I've experienced!


In your case what I have also seen is that there could be some components that when repairing were dislodged off the motherboard. Usually near the battery connector. If you have a microscope I would advise taking the sponge cover off and inspecting the board for missing components.

The display eeprom error must be a problem with the display and motherboard communication. Try another screen that is known good, if its not the screen then I would suspect something on the motherboard or part on the i2c3 line, just a guess but maybe the front sensor flex got torn?

I'm no expert but with bends motherboard components come under strain and the solder joints can fail. Although is a double stacked board (which should be more rigid) can have this problem. I have heard issues of the joints between the 2 boards failing which could be the transmission issue?

This can be an easy hardware issue or a much more complex microsoldering job...


@iphonerepairtom mate, I think it's the FX5 screen that's causing the issue!!

After seeing your reply about using the exact screen I ran to my parts bin and found a damaged but original OLED 12 pro max display. I haven't connected the proximity flex yet so the screen is dim but NO REBOOT!!

I thought I was clever in buying another FX5 panel to rule out a display issue, but it turns out it's either a batch issue or some incompatibility with iOS and the screen. This iPhone is running 16.6.1.

I'm going to fit the proximity flex and check again. I know for a fact the iPhone was rebooting without it being connected anyway.

You should try the same and hope it solves your NAND issue. I once did a board repair on a 12PM with a shorted cap inside the layers and then couldn't restore it (failing at around 18-19% on 3utools). A NAND reball fixed my problem.

Thank you so much for actually making a post about this I2C3 issue because my biggest weakness is to simply suffer in silence in fear I'm judged by people.


@rajajimal not a problem, I am always happy to help. This phone is running the latest software 17.3.1 so I intended to downgrade to an earlier patch to see if that fixes the camera problem. Although it fails even with the genuine screen. I have a feeling its a board issue for my one but will try to swap the camera unit maybe this solve it and I won't have to deal with the software.

That's awesome that I we were able to figure this out, sharing exact details helped very much :)


@iphonerepairtom Also, I thought there was a big thing about iPhone 12 cameras that meant you couldn't simply replace them and hope that they work. See this video

Most likely you'll need your original camera and use the V1S to pull the serial data and write it onto a tag on flex to make it work as normal. I'm actually trying this on a 13 pro max within the next couple of weeks.


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Hi @iphonerepairtom! Sorry for super ghosting you. Life has been a little crazy, but I'm glad I have a rep as a panic log pro. I'm mostly responding for completion's sake, since I suspect you may have sorted this by now, but here's my two sense.

Definitely see your reasoning on pointing to display. Says display eeprom right in the panic. Schematic specifically references i2c3 is related to Touch eeprom as well as some other chips that use Apple codenames, so can't be 100% sure what they are. But could be the display eeprom in question. The fact that it references waiting for an interrupt that is not arriving might also make the think the cable could have some damage. But that's purely conjecture.

Did you ever figure this out?

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Hi, not a problem I have managed to work this out with a member and indeed I can confirm it was the screen. Specifically the FX5 production. I tried 2 new FX5 which both caused the same panic and tried 3 genuine displays, one being the original which resulted in no reboot. Unfortunately I didn't have any other 3rd party display at hand to test if this is a non genuine issue or just the FX5 batch. (Although I did sell a phone with the FX5 display which I didnt notice reboots last year so really not sure if it's a brach problem, software or phone)

Thanks for getting back to me even if it was solved as it can help out other members with the same issue 🙂


@iphonerepairtom Yeah, that's the thing with aftermarket screens, sadly. Could be a bad batch, could even be something like Apple released some update that broke it. It's a bummer, but I'm glad you figured it out!


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Tom will be eternally grateful.
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