cracked fine memory card not working now?

[scibidibibop]

hey guys i was hoping someone could enlighten me, ive just cracked my TA-082 psp to 1.50 and it seems 100% but the memory stick i have now requires formatting by windows to use it, so i format it and its not useable on the psp so i format it on the psp and once i again i need to format it in windows to use it.. any ideas? i returned the firmware to 2.71 and the memory stick works fine in windows and the psp but as soon as i downgrade again its just not able to use without formatting. has anyone seen this before or have any ideas how i can allow it to function properly?
thanks for your time
p.s i have bought a new memory stick just to be sure it wasnt the card itsself

[scibidibibop]

if noones sure on that issue, i was wondering if you can upgrade the TA-082 to a differnet firmware than 2.71 say 2.6 or somethign then downgrade safely with differnet tools to check that? or does the TA version have to be downgraded from 2.71