iPhone developer iH8sn0w has just released a new version of iREB which is compatible with all iOS 4.2.1 devices. You can use it to bypass 1604, 1603, 1602, 1601, 1600 error in iTunes during custom iOS 4.2.1 firmware restore which has been created using either Sn0wbreeze or PwnageTool.
If you have tried updating to the recently released iOS 4.2.1 update on iPhone 4 and encountered Error Code 1013 or Error Code 1611, then you are a not alone. This has been a common issue across all iOS devices updating to iOS 4.2.1 and Apple Support Discussion forums are full of users complaining about this issue.
So you have an iPhone 4 or iPhone 3GS (New Bootrom), running iOS 4.0.1, with SHSH blobs saved on Cydia, and you want to restore your iPhone again to iOS 4.0.1. Now that Apple has stopped signing iOS 4.0.1, you wont be able to restore your iPhone 4 on iOS 4.0.1 by simply pointing iTunes to iOS 4.0.1 ipsw file. Because if you do so, iTunes will throw an error: “This iPhone [your name] iPhone could not be restored. This device isn't eligible for the requested build.
