PSP Custom Firmware 3.80M33 Memory Stick Issues
There have been a number of issues raised with the latest custom firmware, 3.80M33, one of which is problems the Memory Stick Pro Duo over a USB connection.
It would seem that the system decides to default the UMD drive to be the default storage over the USB connection, and not the Memory Stick Pro Duo, as you would expect.
There are a couple of solutions – either disconnect the USB, remove any UMD disc and then reconnect the USB, or press the select button within the PSP’s XMB and and change the USB device settings.
Via: MaxT