My Quo rocked up this week...
Downloaded the Z77MXQUOAS.H3A.816M.ROM file and confirmed it's MD5
I copied it to an ancient 512MB FAT32 USB stick I have here that I use for all my flashes and checksummed it again.
with no drives attached, I boot up and held down the "End" key
Flash utility appeared, so I saved the original ROM to the stick. (it was F2N)
I wrote the Z77MXQUOAS.H3A.816M.ROM file to the board and let it restart twice.
I then powered down and connected up my other USB stick that has ML installer on it.
Before I could even register what was going on, the Apple logo appeared then popped up the ML installer!
I consequently rebooted again with a 60GB SSD attached and installed ML...
That worked well, all is good except for messages.app and audio. TB works but is not live/hot swappable... peripherals must be plugged in at boot time... I haven't even sussed the forums if there's a fix yet... But I'm still pretty happy...
I downloaded 10.9 and applied installed that. All good!
For testing, I even prepared a 10.9 disk on my MBAir via Thunderbolt (GoFlex) and plugged that into the Quo via SATA. It boots and is what I'm using to type this message.
I got legacy FW for my older ZFS storage, I got heaps of SATA ports for current ZFS storage and I got TB for future ZFS storage...
One happy camper here...