It is a known issue, you should contact Intel about it. Intel will not offer any support or care about anything that is going on in this community. I've tested RocketRAID 2720SGL and LSI 9207-8i, both failed to boot, so I've contacted them directly, they said they simply don't care. Maybe there's not enough DZ77GA-70K owners to get their attention.
Same problem I have ... I want boot from 4 x SAS HDD RAID - 10
via LSI PCIe x4 AND/OR Adaptec SAS/SATA RAID controller ... NO WAY !
Please help or indicate a possible solution.
Have you updated with the 0053 BIOS, released in mid-September? This solved the issues I was having.
I have just upgraded and will try during the week end .
Thank you Stephen for the suggestion.