Hi, it's like 1 month that i'm trying to downgrade my old iphone 3G to iOS 2.2.1, but i keep having errors: i tried on my sierra MacBook Pro with the lates iTunes version, pwned dfu, but nothing, i get error 20 or error 1600,1601,1602,1603,1604.
I also tried on an old Vista computer with iTunes 11.0, with the same iphone on pwned dfu, trying either starting from 4.2.1 and iOS 3.1.3.
Has anyone succeded in downgrading his iphone 3G?
Hi,
I've been able to downgrade an iPhone 3G running iOS 4 all the way down to 2, yes. I had to do it in stages, though: 4.2.1 to 3.1.3; 3.1.3 to 3.0; then 3.0 to 2.2.1. All of this was done on a Windows 7 VM running in VMware on Linux, though strictly speaking that shouldn't make any difference.
I took some notes at the time, and this was the procedure I used:
Start on 4.2.1, and downgrade to 3.1.3 by doing this:
1. Using iTunes 12.5 (latest available), downgrade to 3.1.3 in DFU mode
2. With iTunes 10.1.2 and iREB 7, kick it out of recovery mode
3. Activate in iTunes 10.1.2 or greater
Start on 3.1.3, and downgrade to 3.0 by doing this:
1. Using iTunes 12.5 (latest available), downgrade to 3.0 in DFU mode
2. With iTunes 10.1.2 and iREB 7, kick it out of recovery mode
3. Activate in iTunes 10.1.2 or greater
Start on 3.0, and downgrade to 2.2.1 by doing this:
1. With iTunes 10.6.0.40, run iREB 7 and put the phone in Pwned DFU mode
2. Using iTunes 10.6.0.40, downgrade to 2.2.1 in Pwned DFU mode
3. Using iTunes 10.6.0.40, run iREB 7 and kick it out of recovery mode
4. If it doesn't go out of recovery mode, restore 2.2.1 in recovery mode
5. If you still can't get it out of recovery, keep trying until it works
6. Activate in iTunes 10.1.2 or greater
For all these different versions of iTunes, I basically started with the VM with no iTunes installed. I then snapshotted it, installed one version of iTunes, took another snapshot, rolled back to the no-iTunes snapshot, installed another version, and so on until I had multiple snapshots of the VM each with the precise version of iTunes I needed installed on it. This let me easily switch from 10.1.2, 10.6.0.40 and 12.5.x on demand as and when I needed to.
Hope this helps, anyway - as I say, it worked for me. I had to repeat steps 4 and 5 of the final 3.0 to 2.2.1 downgrade a few times before it took, but it did eventually work.
As an aside, I run a blog for people who use older iPhones and versions of iOS as their daily driver, with tips on how to get the best out of first and seoncd-gen kit these days. It's at:
https://olderiphones.wordpress.com/
