Whats the story with the two different builds for the iPod Video?
The 30GB iPod video has 32MB of RAM and the 60/80GB videos have 64MB. Thus, using the 60/80GB build on your 30GB iPod will cause problems. Using a 30GB build on a 60/80GB iPod will work fine, but not use all the RAM. So, for example, if you replace the hard drive in your 30GB model with a different size drive, you should continue using the Rockbox version designated for the 30GB model.