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Announced on October 13 and released October 23, Apple's flagship smartphone for 2020 features a 6.1" OLED display, a triple-lens rear camera system with LiDAR, and 5G. Successor to the iPhone 11 Pro.

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Random stucks and Restarts

Hi Everyone,

I recently purchased my first ever Iphone i.e 12 pro 128gb . Battery Health is 88%. It was running IOS 16.4 well not encountered any issue after updating to IOS 16.5 it started acting weird. Suddenly Hangs Randomly and then restarts. I will share the actual log file. Its always the same error Panic Full {CPU 4 caller x.....} Undefined Kernel Instruction. Kindly Help me with this I'm Really disappointed can't even return / refund this phone as I bought it used. I'm a student and it was my 6 months collection which loss I can't bear. Any help will be appreciated.

Regards,

Tijaz


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Panic Log File

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anyone plz help me through this

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@dadibrokeit I have tried many things including dfu reset now I suspect that it is a hardware defect and to my knowledge it seems bad nand or ram is the culprit.

Alongwith panic full there are aggregated diskwrites and analyticsd.diskwrite logs.

Is there any app that can stress test ram on iphone if it crash on it then its certain that ram has gone bad.

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Hi Talha,

As a software professional with over 35 years experience, I can tell you for certain that this is a software error and not a hardware problem. You've either got some kind of corruption in your operating system or there's an app that's performing an illegal operation.

Either way, the solution is the same; put the phone in DFU mode (google it if need be) and do a full restore. The DFU restore is the most complete rewrite of the operating system possible and will almost certainly fix the error you're seeing.

If you have backed up your phone and are planning on restoring the backup afterwards, be aware that it's possible to back up a bad app then have the restore put that bad data back onto your phone, ending up right back where you were. If you can, I'd suggest just using the phone for a while without restoring it to verify that the error is indeed gone. Assuming it is, you can then proceed to reinstall your apps one at a time, giving it some time between each one to make sure the reboots don't start up again.

I'd like to tag in the esteemed Alisha ( @flannelist ) and see if they have anything to add, being our resident expert on panic logs.

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Hi vojtech I have taken 1200 bursts photos and now it didn't crash tried geekbench , 3dmark wild, antutu all got good scores, now shooting 4k 60 fps lets see how long does it hold.

Hi jerry wheeler,

I appreciate your years of experience in Iphones I will surely try your suggestion.

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@dadibrokeit Software was my gut instinct even before I read your answer. It’s literally saying, “WTF are these directions?” That could theoretically be RAM or NAND or any number of things underneath it all. But this reads as very software to me. Especially since it happened after an update. I would want to rule it out first in any case.

Also. In case I haven’t said it before, I genuinely appreciate you tagging me in these. Because 90% of my why my Kernel Panics page isn’t longer is because there are a lot of panics and I don’t ever want to put anything on there until I’ve done the appropriate amount of verifying.

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@flannelist Lol, good to know; I sometimes hesitate because I don't really know if it's something you're passionate about and want to support, or more of a case where you wrote a paper and now it's a tar baby you keep getting sucked back into. I will continue to tag you when these sorts of issues come then.

Back to the subject, yes 100% agree that it is possible to get into this situation through bad RAM or NAND, but that's definitely the rare exception to an undefined instruction. Basically it means the processor has jumped off into the weeds and is most likely trying to execute data rather than computer instructions.

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updating the issue . one day has passed and I tried to use it as much as i can charged to 100% and depleted to 5% ( installed different apps , games, benchamrks done, 4k 60fps videos approx 50gb recorded ) got no more hangs and restarts I hope it will work fine now but am still worried, because I have done nothing new that could have fixed it perhaps the only thing that was done when the last time crash happened a report just opened up where issue was send to apple automatically and after that I've got no errors till yet.

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@dadibrokeit That makes perfect sense actually. Trying to execute data rather than instructions.

I came at kernel panics from the hardware perspective and I found them to be a helpful took when troubleshooting weird issues that didn’t flag anything in diagnostics, but something was clearly not working. So I just started teaching myself to read Mac panics. It’s the easiest way to verify things like crashes that you can’t recreate. But iPhone ones are more definitive and more likely to be hardware.

So yes. Weirdly passionate about it. Have probably hundreds of saved posts in groups to weed through in my free time, (that doesn’t exist really, but I can hope).

For the record. The thing I can’t get rid of that keeps coming back is radio scanners. I don’t even know that much. But I know enough. Hazards of working for RadioShack for 7 years.

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From the info you have given I would replace the battery, 88% health is not that good and I have seen iPhones produce these symptoms at that point. You could also try connecting the device to your PC or Mac, back it up and perform a restore to rule out a software problem. If that doesn’t fix it you will need to replace the battery.

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Hello, i think is one from the thermal sensor. Most common is sensor on charging flex or on flashlight flex. For identify the problem right i recomend open youtube and play "time count" video, let it till restart and check the time. When is all time restart after the same time then is 99% thermal sensor. For this issue is common restarts every cca 3minutes.

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@vojtech59738 if it would be the sensor, would those not show as faulty in the Kernel Panic? I believe it would and thus I don't think that this is a thermal sensor issue.

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TALHA IJAZ will be eternally grateful.
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