if it loaded ltools, then yea, it was. if you wish to attempt this (but to be completely honest with you, I would wait for a fixed version to come out), then you would need to:
completely remove the current exploit (delete the gamesave).
put the C: partition back to stock.
and then you are ready to rock and roll.
as a side-note, if you have any installed games/apps ect, you may need to move em around to get them to work with this exploit. this installer is ment to be used on a freash xbox.
If you have anything on F: before running this xbox, you need to back this stuff up, because when it is first run on a large HD, it formats the F: partition, so you will loose everything. the installer also warns of this.