Thanks for the info.
Against my better judgement and the instructions, I powered off.

I then popped the MA disc out, powered up, and copied the Ltools package from the memory card onto the hard drive again. I put the MA disc back in, and started the Run Linux save game.
Once MXM booted, I FTP'ed to the Xbox and copied all the files in the /E/backup_linux/ directory to my PC. I then deleted the files and the directory from the Xbox.
This time instead of doing the install UDE, I went and did the backup first. That finished in about 10 minutes, like awal said.
I rebooted, went into the save game, and then did the Install UDE. I chose the same options (UDE1, PBL-Metoo, X2 4981, Evox) and the install finished in about 90 seconds.
Popped the MA disc out and rebooted. Evox! Copied the files from /E/backup_linux/ to my PC again to be safe.
Sweet.

Thanks for the help awal and thanks for the package ldots.