You can try mine if you like (also from one of those adapters).I actually might have a solution... I just need the MEMSTICK.IND and MSTK_PRO.IND files to copy to my memory stick. if that works...
I've also had this happen. The PSP was on an older official firmware and wouldn't read a large Micro SD + memstick pro duo adapter. After updating to the 6.60 official firmware (with a smaller memory stick) I was then able to format the larger one without a problem.I am definitely not an expert as I just bought my very first PSP 1000 and experienced this same problem. I was on firmware 3 and didn't have any memory card except a micro sd and memory stick adapter and the unit wouldn't format the sd card. I ended up getting a 4GB memory stick from Amazon (maybe 12 bucks or so) and when I installed it, I could format it and update to CFW 6. After I did that, the PSP was able to format the micro sd in an adapter. I'm guessing that the firmware update "fixed it", but can't be sure. Good luck!
The duo memory stick does not work for me at all
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I should just give up. Or, it might be the psp itself, or the micro sd card.