I was testing the psn store today with my psp 2000 5.50gen-b, but it doesnt work anymore :Argh:
this is what it appears on screen:
A system software for the PSP system is required.
For update methods,...blah blah blah
i think that sony restricted the access for firmwares 6.10 and up...
i tried the version.txt trick with 6.10 on it as explained somwhere in this forum but it doesnt work =/