I am connecting a G4 iMac (10.4.11) to a MacBook Air (10.9.3) in Target Disk Mode using a Firewire cable and a Thunderbolt-to-Firewire adapter. The iMac works perfectly by itself. In TDM, it shows up as read-only. The Get Info box says I have read and write permissions, but even after unlocking it won't let me change anything, and above that area it says "You can only read." Why is it doing that, and more importantly (especially since I no longer have a Tiger DVD or any other boot volume for the iMac) how do I change it to read/write?