Compatible meaning, can I put a 4GB drive from a 1st gen iPod mini in a second gen iPod mini? Assuming the drive itself is ok, will my iPod work if I do this?
I don't see why not. It would be the same as putting a hard drive from an older computer into a newer one. Of course, the specs on the newer gen iPod mini might be a little faster but if it doesn't concern you then give it a try.