Just tried giving custom firmware a shot with various settings and sadly unit stopped hashing after only a couple of minutes. Will give it another crack here hopefully sometime later today.
Still trying to figure out the value of this firmware upgrade
at stock settings I'm getting 18.9 gHz fans @ 2580 and 3390.
so it's less noisy and generates less profit.
plus I have to pay dev fee 1.5%.
When I undervoltage even less profit and HW errors
I have a watt meter coming in soon I will keep you updated if it's worth it.....
I'm not trying to be negative here but these are my observations so far .
I will post again with energy usage
at stock settings I'm getting 18.9 gHz fans @ 2580 and 3390.
so it's less noisy and generates less profit.
plus I have to pay dev fee 1.5%.
When I undervoltage even less profit and HW errors
I have a watt meter coming in soon I will keep you updated if it's worth it.....
I'm not trying to be negative here but these are my observations so far .
I will post again with energy usage
HW errors @ 18/11 stock settings , going back to bitmain firmware 
...
Hi guys, I guess you're all having the same issue:
Here are some starting points:
for silence and best efficiency / miner lifetime
Expected hashrate: 15Mh/s to 17 Mh/s (my personal preference)
Expected power usage: 700 - 780 watt
set the frequency at "400mhz", set the voltage to "lowest". Now slowly increase the frequency until you see HW errors. When you have a few HW errors an hour you found the sweet spot
set the fan speed manual somewhere between 20 - 30 percent. Chip temp should be somewhere between 75 - 80 degrees max.
For stock performance at lowest possible power usage
Expected hashrate: 18-5Mh/s to 19Mh/s
Expected power usage: 950 - 1100 watt
set the fan speed manual to 50% (adjust this later to your needs. Max chip temp should be 85 deg)
set the frequency at "525mhz", set the voltage to "15". Now decrease the voltage until you see HW errors. When you have a few HW errors an hour you found the sweet spot
For Extreme performance (this is not recommended for 24/7 usage)
Expected hashrate: 21Mh/s
Expected power usage: 1300 - 1400 watt
set the fan speed manual to 100% (adjust this later to your needs. Max chip temp should be 85 deg)
set the frequency at "600mhz", set the voltage to "20". Now decrease the voltage until you see HW errors. When you have a few HW errors an hour you found the sweet spot