Now to install the 6.20 hack!
Download 6.20 PRO (Latest Version).
Copy the 620PRO_Permanent and PROUPDATE folders to /PSP/GAME/.
Run the 6.20 PRO Updater on your PSP and when it runs press X to install and launch the temporary 6.20 hack.
After the PSP restarts, run the 6.20 PRO Permanent Patch.
Press X once to choose to install, then press X again to choose to test it.
If your PSP successfully rebooted after the test, then run the permanent patch again, but this time press X and then Circle to install.
If your PSP did not successfully test, remove your /seplugins/ folder from your memory stick and try again (because not all 5.x plugins work on 6.x).
When you're done, you can delete the files off of your memory stick, since the hack is stored on the PSP itself.