Make sure that if you have a custom recovery that is is updated & double check that it is. Write the version numbers down to confirm, both before & after.
There was an early recovery that could not (CANNOT) be overwritten without flashing a modified PH39IMG file first, then flashing stock or new modified recovery.
If you update with your device with that original recovery, you may be very sorry.
He was talking about the ph39img file we had two floating around for ics the initial leak of ics and the official ics but where are you coming from? Is your bootloader unlocked and what version of android are you on?