I understand that you are experiencing problems using the Aivia Osmium* Mechanical Gaming Keyboard to enter BIOS on the Intel(R) Desktop Board DZ77GA-70K.
In regards to the problem that you are experiencing with this keyboard, sometimes we can get there compatibility problems when some complex devices are connected to the motherboard.
I recommend you to o in BIOS and under the SATA configuration enter a hard drive delay, they will halt the system four a couple of seconds to allow the hard drives to initialize, but this will also allow the system to properly recognize your keyboard.
I will also report this issue as it was not reported to us before.
I think this is bios problem,because I have same problem in my motherboard (GIGABYTE X79 UD5 BIOS ver F9 & F12).
I contact to GIGABYTE . they give me a new test BIOS (F13e) this is OK. now I can confirm the BIOS with osmium.
so I think this is BIOS problem.
I hope this information can help you.