So you don't think the satnav unit is broken - just needing re-flashed?

What is this 'mode 1'/'mode 2' business? I used a CloneCD image I downloaded - how would I know if it's mode 1 or mode 2?

I agree, I shouldn't have messed with it, but I did and now I hope I can get this existing CD out and restore it back to working somehow...