[sinphaltimus]

Try these things and test between each one. Less drastic first -

1: Change your USB Port on the computer, try a different one.

2: Change the usb cable.

3: Format the memstick via PSP.

4. Format flash1 via recovery console/advanced

5. Try a different memstick.

6. Try your memstick in another PSP.

Test after each step.

Let me knwo how it goes...