Help - Upgrading iPhone 3GS 3.1.2 to iOS 4

[Amaresh]

Hey guys,

I've finally decided to upgrade my unlocked & jailbroken iPhone 3GS running 3.1.2 to iOS 4.0/4.0.1. How do I go about this? Should I first mod the iOS4 ipsw using pwnagetool and then use jailbreakme & Ultrasn0w ?

I bought my iPhone off eBay and it came unlocked & jailbroken with Rock so I'm not sure about the SHSH blobs. Is it necessary to have them saved and can I save them using Tinyumbrella ?

I'm running baseband 05.11.07 if it helps.


Thanks in advance!

 

[thelatinist]

Assuming you have the old bootrom and the phone is pwned, just create a custom firmware and restore. Your phone will be jailbroken after the restore, so there will be no need to use jailbreakme. Since your phone is pwned, you can restore or upgrade to a custom firmware without SHSH, but you should make sure your ECID is on file as soon as you can.

For specific instructions, look for a tutorial on iClarified.

 

[eastercat]

Go to the Cydia program. If you don't see a message at the top that says "this iPhone has SHSHs saved for 4.x.x, then your blobs are not saved. If that's the case, you need to be very careful about upgrading.