PSP memory

I wonder if anyone can point me in the right direction or if my suspicions are right.

I dug out my PSP and was trying to update and mod it, it's not seen the light of day in some time so it's firmware starts with a 3.

I bought an adapter so I could use a micro SD card of decent size rather than stuck on the 32mb ones I already had.

The PSP doesn't recognise any memory stick as being inserted when I'm using the adapter and SD card, works fine with the original card and the SD card works fine on the laptop.

I doubt this could be a firmware issue, but the 32mb card isn't enough to update to a newer version

Or could it be as simple as "buy a new adapter"?