Guys its a nexus there is no need to use rootkeeper. On a locked down d2, dx, razr maybe. For the nexus if you are already rooted and unlocked with a custom recovery you could:
a) flash back to stock, relock, wait for ota, reunlock, reroot, and reinstall recovery.
b) either install it prerooted via custom recovery or flash a custom rom like eclipse .
Me personally I choose b because it is less steps (step a for me just will not be an option if I am already rooted unlocked and running a recovery).
So if you want to save steps just follow the steps here and flash the radios and imm76k. I been running it for awhile and it is the exact same thing
[ROM]IMM76K 4.0.4 Stock, rooted, deodex, busybox, zipalign + MODs - xda-developers
Just trying to help.