
Originally Posted by
LocoRon
It sounds similar to the problem I had when I OTA updated to ICS.
In the end, I had to fastboot the system partition, and then I could root normally.
All my personal data and settings were left intact.
Sorry I can't provide more details, but that was the first (and only) time I fastbooted, so I don't remember everything all that well. If you do some searches on these forums for fastbooting Droid 4 I'm sure you can find everything you need (after all, it's how I found what I needed).