How To: Undo a jailbroken Iphone 4 Version 4.2.1 without updating

[Flaime]

Hi there,

So I have a jailbroken iPhone 4 on software 4.2.1 and baseband 30.10.01.

I used the Greepoison method, it all went fine.

I was living in the UK on an orange contract however now I have moved to Australia so I needed to unlock it so I could get a new contract out here.

I bought the Gevey Pro unlock method and put in my new sim however it simply goes straight to the main page - No Sim inserted message.

What I think is happening is that the jailbroken version of my firmware isnt recognising the funky Gevey sim card.

I was wondering if there was a way I could simply restore my iphone to version 4.2.1 not jailbroken. Everytime I try this in iTunes it tries to make me "restore and update" which clearly I dont want...

I tried downloading the firmware 4.2.1 then shift-clicking and selecting the firmware but it didnt work...

Any ideas guys?

Thanks alot,
Flaime

[iYeow]

Almost all members here using gevey sim have their iPhones jailbroken. Jailbreaking is not the issue to your non working gevey sim. Read the instructions on how to use a gevey sim.
As to restoring to 4.2.1 again, you need 4.2.1 blob.

[i.Annie]

I've seen another user with the same issue and a restore to stock fw was required. Apply the Gevey SIM and then if desired, jailbreak it. Jb only after applying the Gevey SIM for the first time.

You need SHSHs to restore to 4.2.1, or 4.3.3 which are probably the best firmware versions to be on. If you don't have SHSHs for 4.2.1 ATM and your phone is still on 4.2.1, you should download iFaith to save SHSHs for 4.2.1. This way you can then use iFaith to create a signed custom FW to restore to.

Edit: the signed cFW I don't think it jailbreaks the device so the Gevey should work. But if I am wrong ... Well you need to get to a stock fw then. And w/o SHSHs a stock fw you can go to is only 4.3.5 which has an awful buggy jb. So you don't want to jb that. But if you can survive w/o a jb and wait for iOS 5, you can use your Gevey SIM at least and have an unlocked phone.

Double check Gevey-3G.com and make sure the SIM works on 4.3.5 though. I think it does but I'm not 100% sure.