The latest firmware for z1+ looks like it is stealing hashrate, a LOT of it. I had it set to 1000 freq with auto freq to 1, and it averaged 1.5gh while still consuming 1170w of power continuously, rejected shares/errors were under 3%. So for that power, the hashrate should have been 4 times higher, I think the hashrate is redirected, getting screwed once with the initial sale wasn't enough...now we get screwed with this.