Ok, so I got my GPS-290 here, I've followed the instructions on the Deniska website.
However, when I try to load MapThis! I get
'Loading USB Accessory Module'
Then the PSP will crash and turn off after 10 seconds. I have set the Kernel to 1.50, and tried putting the files into both, the GAME150 folder and the GAME340 folder. No difference.
What am I doing wrong?