Everyone seem to be upgrading to iOS5 without any problems, but I was plagued with “Unknown Error -23”. Searched online for a few days, asked a few friends and finally found a solution which was to update it manually.
- Download the iOS5 manually. See iOS 5 Now Available [Download Links]
- For Mac users, copy the iOS5 file to “~/Library/iTunes/iPhone Software Updates“. Win XP users “\Documents and Settings\username\Application Data\Apple Computer\iTunes\iPhone Software Update” and Win Vista / 7 users “\Users\username\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates“
- Go back to iTunes and hit “Update”.
Yay. iOS5-ed. Next up iPhone4S.