How do I revert to previous iPhone OS.

I just posted how to revert back to iPhone 3.0 and pasted it below, but I'm not sure how to revert back to ITunes 8.


I had problems with my battery dying after 15 minutes of use, the phone not waking up from sleep mode, and cell signal problems after downloading OS 3.1 and iTunes 9. The problem couldn't be solved immediately because iTunes 9 deletes your previous iPhone backups on Macs. I successfully restored my phone to the 3.0.1 software (easily) after reading through a bunch of long processes on the Internet and trying a simpler way. Here are the steps:

1. Find your backup files on your Mac, it should be a cube icon with a name similar to "iPhone1,1 3.0.1_7A400Restore.ipsw" The numbers after "iPhone1,1_" tell which firmware version it is. My files were in the trash, If you deleted your trash since downloading iTunes 9 it may not be there anymore. You can always do a search in Spotlight to find the backups, in case it's in a different location.

2. If you don't have this backup on your hard drive because of deleting it, I read that you can download it from the Internet. However, I don't know how safe this part is. Google the term "downgrade iPhone 3.1 to 3.0" to find a site that has the 3.0 firmware.

3. Once you find or obtain the restore file/firmware, remember it's location or simply drag it to the Desktop to find it quicker. Open iTunes and connect your iPhone. THE MOST IMPORTANT PART is to hold Option (Alt) and Click the Restore button (Without Option-Clicking the Restore button, you will only be able to restore to the 3.1 firmware). This brings up a screen to find the file on your hard drive. Click the backup/firmware from the location that you had to remember or from the Desktop, and your iPhone will restore back to firmware 3.0.1 and not cause your phone to be useless anymore

Hope this helps.

That depends on what model phone you have. If it's a 3Gs, you can't "officially" go back.

I have original 2G iPhone. I have tried to go back to 2.X OS using iTunes 9, but it won't let me go back. I have OS 2 packages. Do I need to use iTunes 8?

I am trying to go back because I lost wifi when I went to OS 3.

Step 1
Connect your iPhone to the Computer and open iTunes.
Step 2
Get your iPhone into DFU Mode
* Hold both the power and home buttons for 10 seconds
* Then Releasing power and continue holding down the home button until iTunes recognizes a phone in “recovery mode.”
Step 3
Hold down the shift key and hit Restore button and choose the firmware 2.2.1 .ipsw file (for iPhone 2G).
Step 4
Wait and let it do its job. When done restore your backup if any.

Thanks for instructions. Unfortunately will not let me go to 2.X OS, but can go to 3.0. When try to go to 2.x, get error -1610.

If you can get to 3.0, try again & see if it well let you go to 2.1.x

No luck, still get error 1610