Well - it's a long story...
I used the Hack Tools 2.12 - and the wizard said the patches were good to go at step 6.
I then went to my car, and may have screwed up with a twitchy finger - I selected the phatbox, and slipped and selected FM, then back to the phatbox. My phatbox then played some music. I turned the stereo off (with the button on the head unit), and then back on. I then saw the phatbox seek Track 1, then I'd get a No Magazine message - a reboot I think. I restarted it multiple times by selecting the phatbox, (20+ times). I pulled the cartridge and tested it using the tools - where I got the message that it was unsuccessful and to check the logfile. I then tried the tools again, and went back to the car, and tried patching. Multiple restarts later (20+), I again tried the tools....
Each time I attempt to see the logfile at phatsys\logfile, I get the message that it is a corrupted file and it is unreadable.
So after trying that a couple times, I tried unplugging the box from the head unit. Now, I get a solid red light, and the head unit does not see the phatbox. I'm gonna be very upset with myself if I've killed the box, so I really hope that there is some advice for me. I was really looking forward to applying the hack and enjoying the new 250gig cartridge I've put together from the instructions on this site.
Any help is very appreciated.