It's posted in the download section HERE (although Newbie class users can't download from there currently) and it is also archived here: pubrepo.stoker25.com/consoles/ps3/updates/3.55.forCEX.release.20101126.PS3UPDAT.PUP
1: Rip your HDD out of your PS3 and connect it to your PC
2: Format it on the PC
3: Download 3.55 Official Firmware...
4: Install the OFW
5: Now you can connect to the internet...
6: IF you wanna play online update to 3.60
currently you would need to format your harddrive to make sure every thing is cleared, then you need to go to the recovery menu and reinstall ofw 3.55 or if you want psn install 3.60 from the system update.
Yes, your account will still be accessible. Your PSN account's details are all stored online, on Sony's servers.
You can redownload all the content you previously purchased with your PSN account. Just log back in, select Playstation Store in the XMB and then access "My Downloads". It's a list of all the content you own.
Backing up your content is another easier solution. Make sure to delete anything that isn't Sony-approved, including game saves, game data, software, etc. 8GB is probably just enough for your saves and a couple of games.
I have made a full format of the PS3 harddrive and I tried to install the OFW using the USB in recovery mode but it tells me the USB don't contain anything.
the USB is FAT32 formated by default when I bought it so I just slapped on the OFW file on it from my Windows 7 NTFS file system, could that be the cause so I have to apply the file from a FAT32 file system to the USB for it to work propperly?
also since I did a full Harddrive format shouldnt that automatiacly revert it to factory firmware? (so that installing 3.55 wouldnt be necessary so I could just grab 3.60 directly)
no, if it can't find the update it's in the wrong place (wrong path, filename or corrupt on the USB device provided its formatted to fat32). a full format wont change your firmware but you can just install 3.60 directly anyway
If you're planning on going to 3.60 just use system update from the xmb as long as you've already removed all your homebrew and games from the HDD