I'm going to explain exacly how I copied the userbanks to factory quite easily but I'm not responsible if anything goes wrong for you.(this is for windows os)
1.0 Start midiox and select input&output devices in options/midi devices.
1.1 Go to menu view/sysex and then in the new window that appears sysex/receive manual dump.
1.2 On your p12, dump one bank at a time!! When you're done , press DONE in midiox and then menu display window/save as.. Now you've got all the user sounds..
2.0 Start your favorite hex editor which will probably be HxD! Find HxD and install it..
2.1 Open the file and copy the first five bytes. Its going to say F0 01 2A 02 XX, replace the xx with the factory bank, so 00 will be 04 and 01 will be 05 and so on.
2.2 Go to menu search/replace , change datatype to hex-values, paste the 5 numbers in the first field and the numbers with the modified bank in the second field. Press the replace all button.
2.3 You have to do 2.2 one time for every bank, so four times with the added numbers. Save the file.
2.4 Go to menu actions/send/sysex file.
3.0 Don't hold me responsible if this goes horribly wrong..
3.1 See point 3.0
VERY EASY right , not the least bit tedious hehe