Maximus IX Hero wont boot with memory slots A1/A2 populated

[ezpzlmnsqz]

Thought I'd jump in to say that I'm having the same exact problem Gabriel is having: A1 or A2 populated with any memory gives either 55 or cycles 01-03. I have almost his exact same build except I'm using Dominator (3600) 2x8Gb only. Currently have B1/2 populated and it posts fast with no problems (including no BSODs), but having a single DiMM in A1 or A2 causes 55/01-03 variations. Brand new as of 3/11 mobo, memory and CPU (i7/7700). I'm only planning on using 16Gb for the next few months, but if this is a defective board or CPU, I need to figure it out now to get RMA'd.

I am also having the exact same problem with the same set up on the Maximus IX Hero board. As you said, with memory slots A1 or A2 populated, my PC will not POST, giving me the error code 55 and then cycling 01-03. I have an i7 7700K, I've tried multiple memory kits, currently running G.Skill 32GB (4x8) 3866Mhz F4-3866C18Q-32GTZR kit, however, I am only able to POST with 2 DIMMs installed in either B1 or B2. I've tried everything everyone recommended in this thread and no luck.