I specify the coin with c= but it is always the same coin that is chosen.
c= is the payout coin, you want mc=
I am using cpu-multi (tpruvot) and there is nothing such as mc= option.
-a sha256 -o stratum+tcp://ncpool.net:3333 -u kxxxxxxxxxxxxxxxxxxxxxxxx -p c=KYF
For FRANC I should use
-a sha256 -o stratum+tcp://ncpool.net:3333 -u fxxxxxxxxxxxxxxxxxxxxxxxx -p c=FRANC
However cpuminer always get KYF shares.
To get it to mine FRANC I have to disable the KYF coin and then the mining goes to the right coin, however of course KYF is not mined anymore.
If I enable both in the Yiiimp backend, I only mine for KYF but with a FRANC address, I lose rewards.