iOS 8.1 iPhone WDT timeout reboot

As pointed out in other posts, the WDT Timeout is probably not the cause, it is most likely a symptom of the underlying issue. The Reboot/Restart is likely the result of the timeout where the App/OS has not checked in with the "watchdog" and the reaction is to restart the SpringBoard or the OS (paraphrased and simplified explanation)

On my iPhone 5 I can see (many) "*panic.ips" in diagnostics, "WDT timeout". Could be caused by hardware or software bug but I have no way of telling. I have seen the same causes as others: Random freezes and reboots on browsing my apps, using any app, when doing iCloud backups and even not using the phone at all. Most commonly though when doing app store updates it happens.

I have had this issue for a very long time though and can't find cause or solution (tried DFU and normal restore, several updates etc). Interestingly enough I had the issue 1st where the phone would freeze for a few mins and then come back as if noting was wrong (I assumed a faulty app running in background) but I just got used to it as it was not often and did not reboot, however these days it either comes back for a split second then reboots or reboots straight away (I think apple may have changed timeout behavior to restart SpringBoard or the OS if there is inactivity where as before it was more tolerant, older iOS?).

Some days it only happens once or twice, other days it happens 10-20 times. Apple Store diagnostics didn't help. Have also replaced screen and battery after the issue and has not changed it at all. It definitely happens more often if I am updating apps, in fact I can be sure that it will happen most of the time when updating apps. Phone is close to full (64GB with 2GB left) and I fear that it is a hardware issue with the flash storage.

Any news? I can confirm the "It definitely happens more often if I am updating apps, in fact I can be sure that it will happen most of the time when updating apps. Phone is close to full (64GB with 2GB left) and I fear that it is a hardware issue with the flash storage." !

If you believe it is a hardware issue, I suggest you make an appointment at the Genius Bar of the nearest Apple store to have them diagnose the phone, as they can run their diagnostic program on the device. That will help you confirm or deny it being a hardware issue.

And you think that´s the only and right way to make a progress on this? What do you think will happen when I rush in on an Apple store saying "Hey guys, my nearly 4 year old (but looking like a brand new) iPhone has some bugs! Oh and well, the battery and display have been replaced meanwhile!"? If I´d be an Apple employee I´d say WELL, we have the brand new 6S here... or give us 200 $ for checking your old ****** iPhone.

😀

So: Not helpful.

The Genius Bar does not charge to test a phone. Then you think it is a bug, which would be software. To eliminate the thought that it is a bug, you restore the device to factory, then test without adding any additional content. If the device does not exhibit a problem, then it could have been software. If you see a problem, then it is hardware. If your replacement of the battery and display were not done by Apple, then it could be anything that caused the issue, and Apple would not service the phone any longer.

I was at a Genius Bar. They opened it and checked the battery, which was fine (which wasn´t a new fact for me, I used iBackupBot, full charge capacity still OK). They mentioned the not original anymore screen I replaced when killing the original one. They basically told me, to live with the FREEZES/REBOOTS because it´s pretty likely it´s the logic board. Apple does not sell them, it would be 279 € for getting a replacement device (most likely a refurbished). They also recommended to not restore the iPhone, because during this process the restore might fail and lead e. g. to an error 53 code, which means: put the device as defect on ebay.

I did a few further checks by myself like changing battery and display again to other/original hardware, also checked several connectors, removed battery health apps etc.. Didn´t make any difference, still FREEZED/REBOOTED.

Today I did, what I didn´t for a very long time - about the same period of time, the iPhone suffers from those panic.ips WDT timeout FREEZES/REBOOTS: I did an iOS update using iTunes, instead of the (much quicker, but only incremental) OTA update. Using iTunes the full operating system is replaced, not only the changed parts.

After the iOS 9.3.1 update I performed a few tests, which usually guaranteed lead to a FREEZE/REBOOT, like e. g. performing app updates. I collected them the last days, 18 updates without a problem. At the beginning it "soft-freezed" (clock didn´t change for a few minutes), but the hardware was functional (like e. g. working display brightness sensor or still playing music), it ended with "apps can´t be loaded at the moment" message. Performed the updates again, finish. iOS now managed to NOT run into a timeout ("WDT timeout"), there was no REBOOT, no panic.ips. So I guess it was a defect system file/setting, which was replaced by an original/not defect.

I´ll monitor this closely the next days and weeks, but for the first time after 15 months I´m really confident.

To all the others still suffering from the same: It MIGHT be worth a try (iOS update using iTunes). Did you also perform the iOS updates always via OTA? panic.ips seems to has several reasons, so there´s no guarantee it will work - maybe just give it a try (after performing an iTunes backup of course).