There are countless tutorials from a few years ago explaining the relatively simple process of upgrading older iPods to use an SD card. I purchased a couple of really cheap red compact flast SD adaptors from AliX and could not find a way to resolve the ipod folder icon error message. Came back to this recently and found a very old thread on reddit: If you are already have the folder icon error then skip to 1:30 to see the very simple process. I recommend ejecting the SD cards properly from windows and the easiest hex editor I found was the one recommended on reddit. I didn't have any luck on a Mac but Windows was relatively painless. I've upgraded this 4th Gen iPod and a 1st Gen iPod Mini. The Mini was even simpler as no IDE connector to flaff about with. Leave any questions in the comments and share the knowledge with others.