Hi all, I have chucked this together as I am getting PMed alot asking for help on 3GS.
Mods, please check it over, hope it's ok
Right so what I am going to show you is how to restore your 3GS to any firmware even if you don't have the SHSH blobs saved for that version. This also applies even if you just want a custom firmware of the firmware that you are currently on.
First my setup so you know how I did it and what I did it with.
- Windows 7 64bit Ultimate
- iTunes 10.1
- Redsn0w 0.9.6b4
- Tiny Umbrella 4.1.13
- Sinful's custom firmware
- Official 4.1 firmware
Now you know where to get most of these tools, but the firmwares are in my sig for easy access.
Also even though I'm using a PC, all of the above tools are available for mac, so the process should be the same regardless
Alright let me show you the phone we are going to downgrade, it's a iphone 3GS (doh), 32GB. When I got this phone it was already on 4.1 as you can see, and that was the only SHSH blobs I could find for it...... dam it! Oh and that dam baseband/modem firmware......
Also don't forget to back up any important data off your phone before you do this
Note the time on the iphone
If you haven't already, save any SHSH blobs you can, or retrieve them from saurik's server to have them stored on your computer.
Open redsn0w. Now it's going to ask you for the ipsw (firmware) that you have on your phone, IGNORE this. Point it to a STOCK 4.1 firmware, and let it identify.
Identify your phone between the new boot rom or old, if you get this wrong you might have to do a fresh restore then start all of this again. Now if your serial number falls between the 40-44 week you will have to follow Sinful's excellent guide here to find out what your boot rom is
Tethered Boot/Bootrom Info and How to find out what your 3GS Bootrom Version is - SiNfuL iPhone
As you saw earlier this phone is week 33 so I select NO.
Ok now what you are going to do is select only what I have selected on the pic below, DO NOT select anything else, just that.
Now just follow the on screen instructions from resn0w
and you should end up with this
If you didn't then try again
Now just a precaution I always run tiny umbrella, so go do it and start the TSS server, it can't hurt
Now open iTunes. iTunes will detect the phone in "recovery mode" we know better don't we?
VERY IMPORTANT, hold either shift key (if your on a PC) or option key (if your on a MAC), and click on restore.
Find the custom firmware and select it.
Sit back and let iTunes do the rest.
Success, you should be greated with this screen in iTunes
Now set the phone up as a new phone and sync it. Then disconnect it and then connect it and re-sync it. Select it from the left hand pane and restore from back up
Enjoy your phone on a custom firmware whatever version you like. Just to show you here are the pics.
Remember the time from the first screen of the phone?.....
And to check again in tiny umbrella, remember I don't have any SHSH blobs for 3.1.3 for this phone
Well that's it. I hope that helps clear a few questions for you all.
Remember if it helps click the thanks button
GARRHH I forgot to add, I have not tried this with 4.2.1 so if you try it, it's on your head if something happens......