Jailbreaking the iPhone 3G with a modern firmware and no Apple PC

This is another of my "I'm getting old and I really don't want to forget what worked" posts. You likely won't find much of use here.

I'm trying to update my iPhone to firmware 3.1.2 (yeah, 3.1.3 is out but doesn't do much other that rip the ability to tether off the phone again). The key here is that I DON'T want to update my modem baseband as I have the cherished 4.26.08 version that is easily unlockable. I also want to have a version that I can use for tethering.

This would be (probably) much easier if I had an Apple PC for using Pwnage, but I don't. And I decided to spend 2 days figuring this out on my PC rather than going to my sister's house for 2 hours. Duh. I'm not going to bother saying how many times I downgraded to older firmwares / put the phone in a recovery loop / etc.

The key components were:

* Prebuilt IPSW file from someone else built in Pwnage. My file was "iPhone1,2_3.1.2_7D11_Custom_Restore_UNTOUCHED_500MB.ipsw". The key information is:

1. no baseband included
2. "UNTOUCHED" means "unactivated" means "works on AT&T". For now I'm not moving my iPhone off of AT&T. For now. I know, I threatened awhile back, I just didn't get around to it.
3. 500MB ... since Cydia installs to the media partition now there isn't much reason for a 1GB partition

* iReb from iH8sn0w ... this utility allows you to put your phone in DFU mode (hint: put the phone in DFU WHILE the iReb app is running) and cause a whitescreen.

* Once in whitescreen mode you can use iTunes to restore the custom firmware. This allows you to skip the errors that prevent iTunes from otherwise working.

* FAILED DON'T DO THIS: Once THAT is done I used redsn0w 0.9.3 (which includes the IPCC tethering patch) to re-break my phone. To do this, make sure you use the "Already pwned" option in redsn0w. This also gives you the option of adding a custom boot logo.

* NEXT: Install MyWi from Cydia. Launch the "Rock" application and create a Rock ID. Go to settings and enable USB tethering. I don't know if this will break once the app's trial period ends. Quite possibly ... though probably not IF you never open it again. Since I want the ability to connect over WiFi I'm going to spend the $10 on it.

The biggest problem was I wanted tethering. If I would have been happy without it I could have used sn0wbreeze and 3.1.3. I even had that working at one point. I didn't want to us other methods because I didn't want to risk upgrading my baseband.

Apple is unfortunately getting good at preventing or making much harder all the jailbreaking methods used so far. I expect it will get harder and harder to do this on my phone in the future.

If you do this ... I highly recommend keeping copies of all the files you use to do it in case newer versions change the process in the future. Please don't ask me for copies of firmwares, I'm not going there.