Friend has iPhone 3G on 4.2. Can they revert back to 3.1.3?

[WiiDSmoker]

Friend has the iPhone 3G on 4.2.1. Incredibly slow and laggy compared to 3.1.3. Is it possible to downgrade their phone? They aren't hacked nor have ever been.

 

[Myzhi]

Yes. On 3G, you can restore to 3.1.3 and below because Apple didn't start SHSH blobs for them until 4.0.

 

[WiiDSmoker]

Yes. On 3G, you can restore to 3.1.3 and below because Apple didn't start SHSH blobs for them until 4.0.

Just open iTunes. Put phone into DFU mode and then do shift+ in iTunes and choose the 3.1.3 ISPW?

 

[jpetticrew]

Just open iTunes. Put phone into DFU mode and then do shift+ in iTunes and choose the 3.1.3 ISPW?

You got it.

 

[celticpride678]

Yes. On 3G, you can restore to 3.1.3 and below because Apple didn't start SHSH blobs for them until 4.0.

This makes no sense. Apple has been using SHSH blobs for quite some time.

The reason people can downgrade to a lower OS on the iPhone 3G without the need of blobs stored is because the hardware that checks the OS version was not included in the iPhone 3G.

 

[WiiDSmoker]

Cool thanks guys

 

[Myzhi]

This makes no sense. Apple has been using SHSH blobs for quite some time.

The reason people can downgrade to a lower OS on the iPhone 3G without the need of blobs stored is because the hardware that checks the OS version was not included in the iPhone 3G.

Apple started SHSH blobs on 3GS, but they didn't add the software SHSH checks to the 3G until 4.0. Why else do you think there are no SHSH blobs for 3G before than?

 

[labman]

^1+ before the 3GS no SHSH blobs needed after the 3GS yes.

 

[ssdeg7]

TinyUmbrella is your friend.