pinky
Retired
Please, use proper units. They was created for a reason. "B" is not the same as "b", and "MB" is not the same as "MiB" or "Mb".
Every PSX card have 16 blocks. First is for index. Those card probably have switching system on joypad (could not works on PS2, or PSX outside console menu). I have 1MiB card and each of 8 sections can be switched by select+L1/R1 (back/forth). Try something like that.
uLE should shows 120KiB free on empty PSX card (but what it shows I don't know) to be correct.
I did learn about psx cards from you. that's how I was able to inject a save into the psx classic retroarch from my psx card. it's very simple when you see how it's laid out.