As noted above by someone, I am almost positive the new Zig Z1+ is just a firmware update. If I was willing to risk my $4500 ASIC by buying another one and trying to flash it with the updated firmware I would... But I don't have the guts to try it. I can echomost people here, I get an average of about 6.2 Gh/s at 850 and its been stable for 4 days now. BUT that includes about 5-7% stale shares. Hopefully an updaated firmware will come out that allows some of the CGMiner parameters to be changed like Scan-time, Expiry and other settings that would probably reduce stale shares. Hopefully it comes at a decent time.
Either way, to my knowledge, this is the only company selling Lyra2Rev2 asics and it is clearly not even close to as large as Bitmain, so we may get a few months of decent returns before they really flood the market (whenever Bitmain gets around to it)
Also hoping for a new firmware to change some CGMiner parameters.
I exportet the miner.json file over the Settings page but there are not much settings you can change.
Maybe you can add some parameters there, maybe...but i didn't try it.
My miner, compared to yours, is running at 900MHz with an average hashrate of 6.4-6.6 GH/s. My Rejected rates are between 1-3%
But, i need/have to reboot the miner after 24-36h. And most of the time i need to reboot it serveral times before it goes back to normal.