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Since I have a iPhone 4 with v4.0.2 OOTB, I figured I might as well play around with the 4.1 GM pre-public release. Googled for download and found it. Made...
09-03-2010, 08:56 AM #1iOS 4.1 GM (pre-public) upgrade downgrade
Since I have a iPhone 4 with v4.0.2 OOTB, I figured I might as well play around with the 4.1 GM pre-public release. Googled for download and found it. Made sure 4.0.2 SHSH blobs were stored using TinyUmbrella 4.02.05, then upgraded and down graded back to 4.0.2. No issues encountered.
Version 4.0.2 (8A400) changed to v4.1 (8B117)
Modem firmware went from 1.59.00 to 2.10.04
Was able to down grade with SHSH blobs on file and modem firmware restored back to 1.59.00. I did notice that TinyUmbrella v4.02.05 doesn't recognize the iPhone 4 on v4.1 firmware at this time.
09-08-2010, 08:20 PM #2
Update - TinyUmbrella 4.1.2 now available and recognizes iPhone 4 on 4.1.
09-10-2010, 09:14 PM #3
Looks like Tiny Umbrella has been updated again, to 4.1.4.
Anyway, just thought I'd post upgrade / downgrade results in case it is helpful to anyone else.
I upgraded to the public release of 4.1. No issues upgrading or downgrading.
Pleasant surprise - Firmware umbrella v4.1.3 and up will protect the baseband. So using it with TSS server on, was able to upgrade to 4.1 and remain on 1.59.00 baseband. I guess when the jailbreak comes out, ultrasn0w will be usable to unlock the sim. Man, TinyUmbrella is a fantastic tool. The firmware umbrella web page explains everything about the baseband protection.
Last edited by Coop; 09-10-2010 at 09:21 PM.
09-10-2010, 10:26 PM #4
Yeah I played with it too...of course only because Im with ATT & dont need an unlock I belive Dev team mentioned that there's no going back on the bootrom if you upgrade so Tmobile people stay away. The only new feature I see in 4.1 is game center..blah... I downgraded back to 4.0, I needed my jailbreak. Tiny umbrella works like a charm still with no problems.....