Should the demo file be in RAR or Zip?

[silentwing26]

It shows up as corrupted data.

[Kizeragi]

Put it in game, and that's it, demo working and ready

[silentwing26]

I wish. It shows up as corrupted data.

[Weeaboolits]

Do you have your firmware up to date? I think you need that to do it.

[CAVAOUBIEN]

It may be that the data is NOT corrupt, but that instead stupid Windows (or whatever OS is on your computer) has copied the Windows icon files which are not recognized on the PSP. If there are any such hidden icon files, they must not be copied over to the PSP. They will make anything appear as corrupt.

I did my transfer from a shell window (on a MAC) and deleted the icon files added by OSX prior to copying the data over to the PSP via USB connection.

It is indeed in the PSP's Game directory that you should place the UMJ... directory.

[XxKitexX]

It sounds like you're on an official firmware. Go to the PSP main menu, go down to System Settings, and then System Information. What does it say the firmware is?

[D1ABOLIK]

It may be that the data is NOT corrupt, but that instead stupid Windows (or whatever OS is on your computer) has copied the Windows icon files which are not recognized on the PSP. If there are any such hidden icon files, they must not be copied over to the PSP. They will make anything appear as corrupt.

I did my transfer from a shell window (on a MAC) and deleted the icon files added by OSX prior to copying the data over to the PSP via USB connection.

It is indeed in the PSP's Game directory that you should place the UMJ... directory.

I have the same problem. I am on OFW and have the newest update, but it just says corrupt data.