Pangu iOS 9 jailbreak causing mysterious ‘Boot Loop of death’ issue; here’s how to avoid it or get out of it

BY Andy

Published 17 Oct 2015

Jailbreak iOS 9

Pangu team surprised everyone by releasing their tool to jailbreak iOS 9 – iOS 9.0.2 few days back. The jailbreak process has been quite smooth, but like any other jailbreak, it comes with its own set of problems.

One of the most mysterious problems we’ve heard is that the iOS 9 jailbreak is causing “boot loop of death” on certain if not all devices. According to Cydia developer angelXwind, it is caused by “unclean reboots”. She explains:

My theory is that unclean shutdowns are, if not the cause, a contributing factor to BLoDs. I’m saying this because I’ve seen a lot of people get into BLoDs just by performing unclean shutdowns. What’s an unclean shutdown, you ask? An unclean shutdown is a device shutdown that does not properly unmount the HFSJ+ filesystem on iOS — this can be holding Lock and Home to force a reboot, or even a kernel panic can cause these.

So what exactly is the Boot Loop of Death (“BLOD”)?

The Boot Loop of Death (which I will call “BLoD” in the context of this post) is not like the boot failure I described above. The boot failure above is perfectly normal, and the device will eventually successfully boot after a few tries, at most.

The BLoD is a peculiar thing. Actually, I — nor anyone else — really understands what the BLoD even is. Because it can get devices stuck in the boot process for literally hours, it appears to continue on forever.

[..] here’s what is a BLoD:

When you try to boot your device, the untether fails conseecutively for hours — or, perhaps forever. [..]

However, she goes on to clarify that getting stuck in reboot loop after installing an incompatible Substrate tweak is not a BLoD. If your device gets stuck in a reboot loop, you can address the issue by holding the Volume Up trick.
Similarly, if you try to reboot your device, the untether causes a kernel panic or “blue screen” and reboots, and repeats this a few times, even this is not BLOD, as it will allow you to reach the SpringBoard eventually.
To perform a clean shutdown, you should use the slide to power off in the Power down screen. You should avoid force restarting your device by pressing the Home and the Sleep/Wake (Power) button simultaneously.

What should you do to get out of “Boot loop of death”?

If you do get into “Boot Loop of Death” then the only way to fix it is to restore your device to get you out of it.

How can you avoid “Boot loop of death”?

So here’s what you should do to avoid the mysterious “Boot loop of death”. If you’re on iOS 9.0.x, and have already jailbroken your device using Pangu 9 jailbreak then avoid rebooting your device as much as possible. Respring is fine. It also means that you should not allow your device from running out of battery.
If you’re on iOS 8.4 or earlier, and have jailbroken your device, then avoid upgrading to iOS 9, and jailbreaking your device using Pangu Jailbreak until the root cause of the issue hasn’t been identified and fixed.
The issue is partially due to the way the jailbreak works. angelXwind is working to figure out what is causing the issue, and hopefully fix it.
You can check this reddit thread by angelXwind to get more details about the issue.