I want to use my iPod Touch as my iOS 3.x testing device, and need to upgrade it from iOS 2.x. Obviously when I try and do this I get the requested build version is not authorized error, so whats the best way to go about and do this?
Apple doesn't support what you want to do. The only upgrade/downgrade path that they support is to the latest OS version.
The only method that I'm aware of has been built by the jb community. Google for iPhone downgrade and look for a solution that involves connecting to a secret server. I haven't tried this.
@dejo, iTunes wants to install the latest version. OP asked for 3.1. At a minimum you need to option click in iTunes to choose the ipsw file for 3.x. But I think if you try that iTunes will say tough noogies.
The latest compatible version, true. Which for some iPod touches is 3.1.3. Since the OP is still on 2.x, I suspect it might be an older-generation one.
So, I guess I should have just asked the OP: what generation is your iPod touch?
Its a 2G, if I try to update normally it forces the 4.1 update, and if I try to manually chose the 3.x ipsw file the server will reject the version.
So I guess the second question is what the best way to jailbreak a iOS 2.2.1 device so I can save my SSH blobs on cydia and use their server to allow the iOS 3.x upgrade?
I think you don't need to jb the device. You only need to modify your etc/hosts file, but I'm not certain. You probably want to find out the details on another site.
OP, did you manage to sort out the problem without jailbreaking? I am in a similar situation (2nd gen wanting to go up to iOS3 from iOS 2). I figured I would find out if you were successful in the end and also, which firmware source you trusted for the download .