I had the "A2" issue as well when first doing my build.
http://rog.asus.com/forum/showthread.php?44962-Maximus-VI-Formula-Code-A2Mine came to life eventually when I booted my machine with:
1. the monitor connected to the HDMI port of the graphics card,
2. SSD connected to Intel Sata Port 1 (disconnect any other hdds),
3. DVD/Bluray drive connected to Intel Sata Port 3 with Windows 7 disk in the drive (this step doesn't apply to you as you don't appear to have a dvd/bluray drive),
4. Two memory modules installed as per manual,
5. CPU installed correctly with the included intel heatsink and fan
6. All power connectors for motherboard, graphics card, cpu, drives, fans, etc properly connected.
I.e. no keyboard, no mouse, no network cable, etc.
Doing this made it work and see a message about "keyboard not detected". I then connected my USB keyboard - making sure to connect it to the USB 2.0 port! (very important this)!!!! - pressed F1 and voila I had keyboard action and was able to then boot to my DVD drive to install windows (I was doing a fresh install).
MOTHERBOARD: ASUS Maximus VI Formula (BIOS 0804)
CPU: Intel i5-4670k
HDD 1: Samsung SSD 250G 840BW EVO
HDD 2: Western Digital WD10EZEX 1TB Caviar Blue 7200rpm
RAM: 16gb (2x8) G. Skill RipJawsX DDR3-2133
PSU: Seasonic X-Series 750W 80 Plus Gold
GPU: Gigabyte GV-N770OC-4GD
CASE: Fractal Design Define R4
OPTICAL DRIVE: Pioneer BDR-209DBK
MONITOR: Samsung S24C300HL; BenQ E2200HD
OS: Windows 10 Professional
Other: MS Wired 600; Logitech MX 310; Sennheiser PC 151 & Logitech Z150