If you are doing restore to finish factory IMEI unlock you need to insert non-supported Sim card in i Phone first. Also you can use this guide for all times and all version if nothing change.BEFORE we start back up your device in i Tunes or using i Cloud. Step 4: Open i Tunes 10 and restore your i Phone 4 (don’t upgrade) to i OS 4.1. Step 5: During the restore process, you may see 1004 error (firmware update failed) but ignore it.
Step 13: You will be notified when your i Phone is in Pwned DFU mode. Important Note: It is very important that you hold down the Option button else you will end up accidentally upgrading your i Phone to i OS 5, so please follow the instructions carefully.
Promised by Steve Jobs in the beginning of this month, a new version of i OS, i OS 4.1, has been rolled out for iphone 4, i Phone 3GS, i Phone 3G, i Pod touch 2G, and i Pod Touch 3G.
The newly announced i Pod Touch 4G will be shipped with pre-installed i OS 4.1.
Step 5: Navigate back to the Redsn0w folder and launch the Redsn0w application. Step 7: Here click on the “Custom IPSW” button from the options.
Step 8: Navigate to the Redsn0w folder on the desktop and select the downloaded i OS 5.0.1 firmware file (i Phone 4 users – please select i Phone3,1_5.0.1_9A405_and i Phone 3GS users – please select i Phone2,1_5.0.1_9A405_Restore.ipsw).
You will be asked to setup your i Phone either from a previous backup or setup as a new i Phone, select the backup you want for your device (ideally should be the most recent one). After this, you need to follow the instructions in our step-by-step guide to jailbreak your i Phone on i OS 5.0.1.