I have S5s, so I could help with testing, too.
So far I've just been studying how it interfaces to the hardware - mainly the kernel code so far.
Perhaps it's best if you start at the userspace/cgminer side so we don't overlap?
I'm about to be AFK for a bit, but maybe later we can discuss further on IRC
Wow, I'd really like to see BFGMiner on my S5s!
Currently using the cgminer 4.9.0 version, but that is a hassle if you reboot the machine, you have to replace it each time...
Didn't spend a lot of time on that, besides putting the binary in /config (surviving reboots); together with a stupid script that stops 4.8/replaces and starts 4.9.
Any idea how to edit the Firmware in the eMMC?
Also the options is a mess... If you find any reference of voltage settings (in hex) that would be interesting (found different answers on that, and obviously interested in the correct one).