5.00 m33 glitch?

A friend of mine has an 8gb memstick, and he told me it wasnt reading on his psp.
when he went to the game folder on the xmb it showed he had no games. (yes the were .iso and .cso files and yes they were in the ISO folder)
but just to check and see if it was his psp, i threw his memstick in my psp and it didnt read that there were any game files either, doing this, i put in my memstick again, and now its not reading my games?!

any ideas?

P.S.

sry for not posting any news recently, I've been studying for my finals so i can get out of high school.

I solved this by formating my memory stick and adding my files again.

is there any way to keep this from happening again tho?
id like to avoid it if i can, cause its just annoying.

Edit*

this problem isnt fixed.
it did it after i used the home button and quit the game to the xmb.

Edit2*

it turns out, that the new rockband unplugged games as well as some other games such as Dj max for the psp have a patch or sumthin that blocks custom firmware folders. i guess sony is doing everything it can to stop us. i have a feeling that the "leaked" rockband game for psp wasnt dont by a third party.
sony may have leaked this purposefully so try out their new security.

http://www.dark-alex.org/forum/viewtopi ... 7cf601ef33
http://gbatemp.net/index.php?showtopic=155141

I was going to mention the anti-CFW addition but apparently you found that out according to your barrage of edits.

i read that if rockband deletes your game folder from PSP/GAME.
it said it only deletes the folder if it is empty. the solution is to put any file in the PSP/GAME directory.
it was suggested to put an .txt file cause they are small...
good luck

yea it works. it took me a few tries but you have to completely delete the game folder all together and then make a new one in all caps, and save the empty .TXT file in it. easy easy.

thanks anyway.