Hello everyone, I have a very serious problem and I hope for your help! Late 2012 iMac with 1TB FusionDrive, I installed Mavericks GM but I wanted to go back to Mountain Lion. I can't do this with the Recovery HD partition because tell me to install only Mavericks and not Mountain Lion. So, I deleted from Terminal with the command diskutil the Recovery HD partition and rebooted into Internet Recovery. Now Internet Recovery suggest to install Mountain Lion but when I go to select the disk destination is gray and can't continue. Into Utility Disk I can't format Macintosh HD "Volume", as locked!!! So, the problem is that into Internet Recovery I can't select Macintosh HD Volume as destination for Mountain Lion, I doon't have the Recovery HD partition, I think that removing the Recovery HD partition my Macintosh HD Volume has lost the correct structure. What can I do? Any solution, for example, to erase all and recreate the FusionDrive structure/mapping partition?