There's no need to uninstall before installing v0.3, the installer will take care of everything for you.
For a complete uninstallation if you want, you need to do the following:
- Delete the /seplugins/pikey folder from your memory stick
- Remove any mention of pikey from the /seplugins/*.txt files
- If you flashed pikey for v1.50 mode, then in the OE recovery mode:
- Go to Advanced, and Enable USB for flash0
- Open the /kd folder in flash0, via your USB connection
- Remove pikey.prx
- Edit pspbtcnf_game.txt, and remove the '/kd/pikey.prx' line