I'm using 3.03oe-c firmware and have a Sandisk 1.0GB ms duo bought from Target(i.e. legit). This may occur on other custom firmware but have not and do not want to test on other firmwares. maybe someone else can try on some other firmwares.

Basically I format the memory stick through the 'system->format ms'. Then I connect through USB and use the DOS 'chkdsk' command on the psp. It scans the drive and gives me 'bad links in lost chain at cluster....' errors.

As a test I did format my stick through my computer and then copied the files/directories to my psp and chkdsk was fine.

Does anyone know if this is how the PSP formats the mem stick? Does this happen with the sony firmwares?

Well im not totaly sure but i did once have a corrupt game save that could not be deleted when using a usb but when i formated it on the psp it deleted it fine im not too sure why you cant delete it when your on ya pc but just leave it at that lol