The reason we do this for the Id is that we do a lot of work on the firmware so it's ready for users to plug in and use. We don't want users making any changes that could potentially break the Id firmware beyond repair. If you're looking for Pi that you can customize, on the Linux board you can find an ARM version of Media Center. This is just Media Center and not the Id firmware, so you'll need an SD card with an OS, but you'll be able to customize it. Also, the Id Pi license won't work, so you'll either need an MC Linux license or an MC master license.