You will need to take off EVERYTHING.
The knobs (just pull them up), ALL of the little nuts on the input jacks (a pair of pliers to get them loose and then just your fingers), the 4 little Phillips screws over the MIDI jacks, and the 4 T10 TORX screws (which you already know about).
Once inside (if needed) you can use the T10 driver to remove all of the screws mounting the board (I think there were 10 of them). But that's only necessary if you need to access the SD-Card, I think.
It's actually quite simple, but don't try forcing anything. It should come apart very easily if you remove everything correctly.