Does 5.1 update baseband?

[mtmjr90]

Hey,

I'm itching to update to 5.1 just because... I'm also jailbroken (Verizon 4S on 5.0.1 baseband: 9A405).

I've saved my SHSH blob with tinyumbrella so I can go back and rejailbreak if I want to. But, I've been waiting for an unlock so I don't want to risk updating the baseband.

I'm relatively new to how unlocking/baseband updating works on the iPhone, so any help is much appreciated. Thanks!

-mtmjr90

 

[evoKY]

If you have the 4S saving your SHSH blobs won't help because the A5 was a different exploit from A4. I did read that the baseband was also upgraded with 5.1

 

[mtmjr90]

Thanks for the reply! So are you saying that even if I've got my 5.0.1 blob saved, I wouldn't be able to downgrade from 5.1 to 5.0.1 and jailbreak again? Why would that be?

Sent from my Galaxy Nexus using Tapatalk

 

[evoKY]

Correct, it was issued by the dev-team
Dev-Team Blog - March Mayhem


Soon after 5.1 appears on Apple?s public servers (i.e. iTunes starts to offer it), Apple will stop signing 5.0.1 SHSH blobs.
If you have an iPhone4S, the basic rule above is really the only rule: *you cannot restore back to 5.0.1 once the 5.0.1 signing window is closed, no matter what (even if you saved your SHSH blobs).

 

[Massie]

Thanks for the reply! So are you saying that even if I've got my 5.0.1 blob saved, I wouldn't be able to downgrade from 5.1 to 5.0.1 and jailbreak again? Why would that be?

Sent from my Galaxy Nexus using Tapatalk

That's true--as mentioned above, the newer devices aren't vulnerable to the exploit (called limera1n) needed to downgrade. Earlier devices (iPhone 4 and before) are vulnerable; devices after that are not, and use a different exploit to jailbreak (which alone is not enough to downgrade).

 

[mtmjr90]

Hm...the method I use to downgrade is to simply restore the 5.0.1 ipsw while tinyumbrella is running a TSS server to "sign" the older firmware. As far as I know, there's no exploit involved, limera1n or otherwise. Is there something I'm missing?