DO NOT try to run qunlock on a maxtor 120GB drive, apparently it kills them. qunlock is for Quantum drives, few things have changed with the Maxtor 120gb's, qunlock used to work on the older Maxtor's but not the newer ones.
I've got 2 x 160GB Maxtor's in my Tivo, and MFStools 2.0 unlocks the drives automatically when I put them into my PC.

Here are a couple of threads about it at the tivo community forums...
Maxtor & Qunlock

And for anyone who reads this in the future who hasn't seen the other threads (or missed it here): DON'T RUN QUNLOCK ON ANY MAXTOR DRIVES EVER FOR ANY REASON!