I was consistently getting a code 34 on POST with a Maximus IV Extreme-Z board, thinking I would have to RMA it. The debug code would go all the way up to 98, then go back down to 34 and had 1 long beep, 4 short beeps, a brief pause, then another short beep.
RCPoster said the issue was ROM init, so I thought the BIOS chip was bad. I tried flashing the ROM via USB/ROG from both a FAT formatted stick and FAT32 formatted stick, to no avail. The USB stick would flash for a few seconds but the BIOS light on the board would only flash once.
I finally gave up left the machine plugged in and came back from work yesterday, and noticed that the board code now said AA (sleep mode I believe). Well, this was new, so I reset the machine, and lo and behold, it went into the BIOS/UEFI! The 34 code turned out to be a CPU thermal warning. I didn't hook up any of the thermal sensors, and I doubt the CPU was really running close to 200F, but I just hadn't been getting any video output at all, and now I was (and I had tried 2 different cards). You might try hitting the F1 key once you get the 34 error.
Also turned out 1 RAM module wasn't seated all the way, but I don't think it was in any way related to the issue since I had tried extensively with just one stick in various slots and had got the 34 error every time.