Hi,
From its manual:
Memory card—Secure digital (SD) or MultiMediaCardTM (MMC) 128 MB is the largest memory card tested by HP.
Larger sizes of cards have not been tested, but they should work - use at your own risk. This product only supports the
use of MMC memory cards that have been verified compliant to the MultiMediaCardTM specification as of January 2000. Compliant MMC memory cards have the MultiMediaCardTM logo on the card. The following memory cards are available from HP:
• 32 MB SD card—C8895A
• 64 MB SD card—C8896A
• 128 MB SD card—C8897A
Finding a right card now is a big problem.
Full manual: http://h10032.www1.hp.com/ctg/Manual/bpl51337.pdf
Hope this helps.