You can update the SU on 173 if it asks for it while on the device itself.You click the notification. May also need to update Superuser.
I tried, I do believe. It just gave me an error that it could not update Su. And I downloaded the newest Superuser as well. I just can't figure out what went wrong. >< I did the RSD back to .744 then OTA updated to .748 and everything.