which MapThis are you using? the one for generic GPS receiver or the one for the PSP290?
If you're using the one for the PSP290, which version firmware are the prxs from?
What kind of map, size, zoom level are you using?
Try making a smaller map and test to see if it still crashes.
Also, the latest version for generic GPS is 0.488 and the latest for the PSP290 is 0.48.
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