Well, I had an unofficial JB ROM on my GNex, and when the update came out I thought I'd just go with that instead. So I made a backup of my JB just in case, and then deleted user data and restored my old ICS backup. I guess I had to have dev options off in settings, from what I read, becuase CWM gave me an error that it couldn't restore /data. So I tried to go back to JB and thought I'd just have to download the ICS image straight from Google. I got the same error! So after numerous attempts to get anything going, and all kinds of fiddling until well after 3 AM, CWM can't mount /sdcard, the bootloader has the fastboot status as FAILInvalid Command when I plug my phone into the computer, and I have no ICS or JB. I don't know what to do, because I tried searching the mounting issue and the fastboot issue, but it seems that no one has had both of these problems at the same time before. Lucky me. Please, any help would be hugely appreciated at this point! I think it's safe to say that if I get this sorted out, I'm going to stay well away from rooting and flashing ROMs.