Originally Posted by TobiSGD
If I do understand you right, you want to replace Microsoft's firmware with Linux. I don't know if the license allows this, but I would assume that at least in some countries it is illegal to do so. So I don't think you will get advices here.
If Linux is simply replacing Microsoft's firmware, wouldn't that be the same as buying a PC, and replacing Windows with Linux? Using Linux to modify the firmware would probably be where licensing issues would start.
At first, I was thinking the OP wants to put Linux along side the firmware, so the Zune will still have it's firmware, but will be able to boot Linux on a PC when connected. Or does the OP want to boot Linux on the Zune itself like iPodLinux?