I used wigs nexus root toolkit on my n7. With it I unlocked the boot loader, rooted, and installed a recovery. I believe I have a nandroid of this point. A little later, I wanted to test ART runtime, so I got the CM 11 nightly. I could not boot to recovery, I just got the android guy with the warning triangle in his guts. So, I went to the root toolkit and it was able to boot my tab to recovery. I never got around to asking about it, but that was weird thing one. Since I could get to recovery now , I flashed the nightly and gapps. No problems. With art activated there were some crashes and incompatible apps, so I returned to dalvik. Now, the next issue. CM11 has been fine, and until today I don't think I used any root required apps. Today I installed titanium backup to move an app and data from a phone over. The first launch of titanium said I had incomplete root. I tried to restore the desired app and it crashed. The second launch said I had root, but supersu was better. It crashed on restore again. I installed supersu, opened it, granted it root from the existing su, installed the binaries, and rebooted. Now I have no root at all! Any pointer or advice are welcomed. Since I don't need art yet, I may return to rooted stock,but that still won't fix the recovery issue. Thanks!