Downgrading from 4.0 to 3.1.2 with SHSH in Cydia

[jjk454ss]

Not sure if this is something that we can know for sure yet, but if iPhone 4.0 comes out and I install it, will I be able to use the SHSH info on file with Cydia to downgrade back to 3.1.2 if I decide to? Does this work with the dev versions of 4.0 right now?

 

[Vinnie Madrox]

I'm gonna throw out a guess, and say no. It's my understanding that when you upgrade firmware now, it also updates your baseband. that being said, an older firmware won't run on a newer baseband.....and you can't downgrade the baseband.....



but again, that's just me guessing.,....

 

[bytethese]

Not sure if this is something that we can know for sure yet, but if iPhone 4.0 comes out and I install it, will I be able to use the SHSH info on file with Cydia to downgrade back to 3.1.2 if I decide to? Does this work with the dev versions of 4.0 right now?

I would say yes, since the SHSH blobs are saved, you could point your iTunes to Saurik's server and restore the previous firmware. What you wouldn't be able to do is downgrade your baseband. I have heard mixed reports of using newer baseband with older firmware. However I hear that 3.1.3 and 4.0 should be able to be unlocked after it's released.

Lastly, this may help:
http://justanotheriphoneblog.com/wordpress/iphone-tips/quick-tip-downgrading-4-0-beta-to-3-1-3

 

[jjk454ss]

Thanks for the replies. I'll guess we will know soon enough. I'd like to upgrade to 4.0 right away because I'm impatient, but I'd like to be able to sell my phone unlocked when the new iPhone comes out.

I guess it doesn't matter because I won't be able to keep 3.1.2 when 4.0 comes out anyway. And like bytethese said, good chance I will be able to unlock 4.0 soon anyway.

 

[scirica]

Think I'm going to wait until the 4.0 jb/unlock comes out for 3G(s) and play with that for a few weeks before diving into the new hardware. Should be a fun day today in MacWorld.

 

[jjk454ss]

Think I'm going to wait until the 4.0 jb/unlock comes out for 3G(s) and play with that for a few weeks before diving into the new hardware. Should be a fun day today in MacWorld.

I would if I wasn't so darn impatient. I know I wouldn't be able to wait.