the 0.7.2 update cleared automatically.
I did the factory data reset as you suggested (via poweroff | power/volume up/volume down | Recovery | volume up/volume down | factory data wipe), and I've reinstalled RootExplorer, but now I need Rootkeeper to get my root back (presumably, it saves the root somewhere that doesn't get factory wiped). Once I have root I can move the JB update to cache.
I would think that I could use the utility from the first post to reinstall Rootkeeper via AP Fastboot, but when I do it says "Make sure Debugging is enabled on your phone" and hangs. Maybe it is expecting straight 4.04 ICS, and doesn't like my half-upgraded version?
In any case, I can't get Rootkeeper that way. Is there another way to get Rootkeeper?
So did you turn on USB debugging??
Voodoo rootkeeper is in the play store.