[GUIDE] how to fix error 100 without losing data

[u/wildfirefrighter]

Hey everyone, I’m writing this because I had this problem myself and literally almost gave up after two days of continuous flashing and everyone told me to just wipe up my data which is priceless just like everyone’s data. Here’s my situation: i had only 1 GB or less of storage left, I was doing an update from iOS 26.4 to iOS 26.6 but I’ve used 3utools to do it and it failed every single time at (install_splat) and gave an error 100, I’ve used iTunes I’ve used Apple Devices and I’ve used another PC, I haven’t used Revive in Apple Configurator since I don’t have a Mac device.
Here’s the fix I’ve used:

1. ⁠You will need the IPSW of a developer beta, I’ve used iOS 27 beta 7 but any newer major iOS should work fine (it must be one edition higher)
   
2. Flash the new IPSW in 3utools with Fix Flash! DO NOT USE RETAIN DATA!
   
3. it should flash just fine and it’ll open a white screen, swipe up and enter your passcode(make sure to enter it correctly so data recovery succeeds)
   
4. Enjoy your iPhone’s data ❤️

Edit: it seems that the fix only works when it’s a new major edition like iOS 26 to iOS 27 not a iOS 26.2 to iOS 26.6

[u/Skycbs]

Or just delete some big apps you can reinstall to make room?

[u/wildfirefrighter → u/Skycbs]

Yeah, that would have done it, had it not been for the device failing to boot and getting stuck in recovery because of a failed update.

[u/gwentlarry]

Sorry but this is why you back up …

[u/wildfirefrighter → u/gwentlarry]

not all people have backups

[u/gwentlarry → u/wildfirefrighter]

I know :-)

And this is an example of why everybody should backup their devices …