There seems to be a bug in Yosemite Recovery Update 1.0 which no longer allows the recovery hd to boot from the startup manager available when booting up by holding down the option key. Command R and Command Option R may still work though. If this is affecting you, here is a workaround to get your old recovery hd back. I would recommend not installing the Yosemite Recovery Update again until apple fixes it. 1. Download the Lion Recovery Update from http://support.apple.com/kb/dl1464 . (And before you ask, YES. I mean LION recovery update!) Make sure it is in your downloads folder. If you still happen to have the yosemite DP1 installer somewhere, right click on the Install OS X 10.10 Developer Preview.app file and click Show Package Contents. Go to Contents/SharedSupport/. Copy the InstallESD.dmg file into your Downloads folder. If you don't still have the DP1 installer, you can get it again by redownloading from your purchases tab in your mac app store. 2. Download and decompress the file recovery.sh.zip from http://4unitmaths.com/recovery.sh.zip and move recovery.sh into your Downloads folder if it's not there already. 3. Open Terminal and type the following commands: chmod +x ~/Downloads/recovery.sh sudo ~/Downloads/recovery.sh 4. Wait a few minutes for it to finish and return back to a prompt. Reboot with holding down the option key to test your 10.10 recovery partition.