You don't need Cydia to boot it. You need redsn0w to do a tethered boot.
Download redsn0w from iClarified. Or google redsn0w 0.9.9b7, and download it from a trusted site.
Open it, and have the 5.0 ipsw ready.
Choose the ipsw when you go into extras.
Then choose boot now.
If you aren't planning on having it jailbroken, just restore with iOS 5 normally in iTunes. It wipes all the data, plus if you want it JB'en again, you can do it freshly.
11-02-2011 10:39 PM