That thing is so sexy, you could still consider adding leds to the support structures, blinking at shares found so it'll cause epileptic seizures.
Did reprogramming p 0 or p 3 target solve the issue with your cairnsmore which hashs on different speed on the two serial ports ?
If you can confirm this then it looks that the twin_test bitstreams doesn't need another core.
My hashing result over last 3 hours shows more than 355 Mh/s on 2 FPGA cores, if we could use 4 cores we are near the 800 Mh/s target. I understood why icarus fails with the wrong TX/RX connection (between P3 and P2?) but if twin_test works as standalone core there is only a stable clock and the rx/tx to the array controller / FDTI required??
The big question is if we really need a jtag? If we
flash the bitstream with xc3sprog , it doesn't need to reprogram it via JTAG like the ztex board required on every power cycle? I guess after programming the tml bitstream uses the serial connection for transferring data.
Hpman