undo upgrade from avic n1 n2

Hi every1, I recently got a pioneer avic n1 from ebay. Unfortunately I dint have the n1 original disk, so I used my friends disk. I dont know whether it is n2 or n3 but basically it upgraded my system. Now I have a n1 original disk but doesnt work because of the upgrade I did. I see there is a topic that already covers this but it doesnt tell me what to do when I am in that menu. I tried erasing half of it but still it doesnt work. So, I would be really really grateful if one of you guys can tell me what exactly to erase when I am in that menu. Thanks -Andy-Andy

Have you tired hitting the rest button?Cris

check the forums at the  www.avic411.com .  I know I've read the process there.