Need help to upgrade 3GS 3.1.2 to 4.0.1

[Metalloid6]

I have a 16Gb 3GS and I used blackra1n to jailbreak it in version 3.1.2.

I want to upgrade to 4.0.1 because there are some iTunes apps that require iOS 4 to run. I haven't kept up to speed with all the updates and jailbreaking since I originally did it several months ago.

Can someone give me some detailed step by step instructions with what I need to do to upgrade? I have a windows pc. Thanks to anyone that can help. I needed some serious intervention the first time I did it.

[jkmonkey]

Download a 4.0.1 from the downloads section of this site. Then hold shift while you click on restore in iTunes. Then select the firmware you downloaded.

[Metalloid6]

Is that all I have to do? I don't have to go to jailbreakme.com?

Will all of my current cydia apps still be there?

[jkmonkey]

After you've gotten it restored to 4.0.1 you will have to go to jailbreakme.com with safari on your phone. You'll have to reinstall all the packages that you've gotten from cydia. There is an app in cydia that makes that relatively painless though. It's called pkgbackup. If you run that then sync you phone then after you restore and jailbreak just go to cydia and install pkgbackup. Then you go into that and hit restore and it puts everything back.

[Metalloid6]

Thanks for clarifying.

If I have files saved in folders in a cydia app directory, then will the files be lost as well?

That's my last question. Thanks.

[jkmonkey]

Yes those would most likely be lost also, so you would probably want to back those up before you do the restore.

[Metalloid6]

Awesome. I paid for pkgbackup and tried to install. It won't install and I get a size mismatch error. I emailed them to hopefully resolve the issue.

You ever encounter a problem like that in cydia?

[jkmonkey]

No, I've never run into that before. try rebooting your phone, then reinstalling it