While away from home, I updated my iPod Touch (2nd gen.) to iOS 4.2.1 using a MacBook Pro running MacOS 10.6.3 and iTunes 10.1. I returned home, plugged the iPod into my PowerMac G5 with MacOS 10.4.11 and iTunes 9.2.1 and, yup, got the message that I will need to install iTunes 10.1 if I want to sync with iOS 4.2. Of course, iTunes 10.1 is not compatible with MacOS 10.4.11.
I would gladly downgrade the iPod Touch to iOS 4.1 but I cannot find it on the Apple website. I do have a file "iPod2,1
4.1_8B117Restore.ipsw" in the iPod Software Updates folder in iTunes which might work, but as the iPod Touch is no longer recognized, I do not know how I would do that.
I did search the forums for "iOS 4.2", "iTunes 9.2.1", "iPod Touch" etc. but I did not use the term "downgrading". So I didn't find the answer to my question.
I am not a big fan of Leopard, especially as there are Classic applications that I still use (no Classic in Leopard), but the PM G5 has more than enough hard disk capacity to install Leopard on a separate partition or drive so that I can run iTunes 10.1. If rebooting is a PITA, then I can use the MacBook Pro (running OS 10.6) to sync the iPod Touch.