You are luckier than I, enjoy it sir.

After spending several hours trying random things suggested all over, I've still had no luck. One rig starts off good at about 450 Gh, but slowly goes down to 250-350 Gh. I have to hit start/stop every 5 minutes to keep it above 400 Gh. I am now switching out H cards in different slots to try and see if I can come up with a card configuration that will run more stable. I read putting bad cards in the last slot of every bank helps.

The other one can't even pull 0 Gh. I'm thinking it's possibly a bad M board, or something is wrong with the firmware. There are others with this problem.. so I'm glad knowing I'm not alone. It sucks having an $8,000 bitcoin mining rig and it can't even do 0.1 Gh. I'm gonna keep messing around with it, but at this point I'm at a loss as to what to do.

Thanks for the heads up, I'll give it a try. 

 Ditto here; seeing the exact same thing Have to keep restarting it every 5 minutes to maintain hash-rate. I tried swapping all sorts of combos of H-Cards in different slots with no discernible effect.

 I feel your pain, bro.

 To be absolutely clear, I'm not calling anything bad. Just a bit surprised that we seem to collectively be having some trouble getting these v3 rigs humming along, stably.

 Eagerly awaiting updates and info on how to get our babies nice and happy.

Anyone here have any V1.2 h-cards they'd be willing to sell? (ie the ones that work with v2.3 m-boards NOT the new PCI connector style m-boards).

+1 looking for them as well

I also had problems with my BFSB old style M-board/H-boards, maybe this will help: https://bt.irlbtc.com/view/250249.msg3454967#msg3454967

It could be that your M-board has issues.
I bought an extra M-board and am now using it too.
None of my M-boards is filled with 16 H-boards.

H-boards that didn't went over 25GH/s got the pencil mod applied and are now doing better.
I have fans laying on top of the H-boards, blowing down. The fans keep the boards from wiggling.

Good luck.

It was impossible for me to run more than 13 H-boards on a old style v1 M-board. The 14th board will always report zero hash rates.
 I think it's an issue with the SPI clock signal. That is why new H-boards have 4 SPI channels.
 
check line 121 of spidevc.cpp

so my miner stopped overnight inexplicably (charts indicate it unning stable between 76-79GH (2 cards) for 36hrs) and I rebooted it and charts indicate that caused it to work for about a minute or 2 then stop again.

using SSH commandopt/bitfury/start-miner.sh, i get:

cp: cannot create regular file `/run/shm/stat.json': Permission denied
cp: cannot create regular file `/run/shm/.chip.cnf': Permission denied

Is this an SD issue or something else?

How I fixed my problems (two rigs stable 473 Gh and 517 Gh- with 1 dead h board on the slower one):

(I don't take credit for these fixes, some of them I found out on my own and some of them I read from other user's experiences.)

I needed to find a way to keep the cards stable, they come with crappy 1x PCI connectors and are really wobbly, especially when being blasted by fans (which is necc. to keep them cool and stable). The movement in the cards was causing the rig to slow down slowly over time until the affected cards eventually ended up at 0 Gh. To fix this I used two rows of electrical tape along the top of the cards to hold them in place better.

Cooling may or may not have been an issue. I added an extra box fan in front (two box fans now) and also two computer fans blowing air down on top of them for added air flow.

I was under the impression that two full rigs would run on one 1200 watt power supply. It turns out that seemed to be overloading the PSU (a nice gold rated ASUS). I ended up using a separate PSU for each rig and that got them both mining. I think this is the main reason why the one was getting 0 Gh and wouldn't mine. As soon as I put it on its own PSU it started working fine.

I put slower H cards in the last slot of each bank to keep them from interfering with other H cards. If you have one bank that is not working but all the rest are, this is likely the issue. If the card in the first slot of each bank is not seated properly, the rest of the bank will not work.

I hope this helps someone and saves them the 16 hours of their life that I just wasted. Now... I wish I would of realized all this before spending all night messing with firmwares... flashing sdcards... installing a different OS... trying BFGminer... trying cgminer... etc. :rolleyes:

My phone messed up while uploading, but a couple pics: http://imgur.com/a/9vDAm#apBFVy5