v12.1:

- slightly improved speed for some cards, about 410H/s on stock 390X, 450H/s on stock Nano, 290H/s on stock 280X, 300H/s on stock RX480.
- slightly improved stability. If it is still unstable for you, reduce "-i" value.
- fixed issue with wrong hashrate when "-li" or "-ttli" options enabled.