I just bought a 160gb Slim, CECH 2503A, the last model before the new ones that (for now) cant have CFW installed. Ive already got a 40gb phat with CFW on it but want to update it to OFW to use legitimately on PSN, but I dont want Sony knowing I had CFW on it at and ran homebrew/backups before. I did a HDD backup just before I installed CFW on my phat, if I format my HDD, restore the backup and go online and update to 3.70 is that as good as done ?. The reason I installed CFW on my new PS3 is because my Phat's fan has been going into overdrive when playing certain games for over an hour, like GOW3 and Uncharted 2, but LA Noire would make it do it after 20 minutes so I figured its on the way out. I can always replace it a new PS3 that (for now) can only have OFW. So, any tips before I go back to the world of official Firmware ?.