Hi Tomin
To answer your first question last, you can check the FTDI by brindging between TX and RX and confirming that anything sent is echoed on your terminal emulator.
Generally it only damages the sanguinololu if 12V are connected in the wrong place, connecting the P2 cable back to front does not normally have this effect however it clearly did in your case. If its 12V in the wrong place (for example with the P2 header put on incorrectly and then the P2 cable plugged in) then more than the ATMEGA could be damaged, its hard to say. I would try with the ATMEGA first and see how you get on.
Regards
Tony
To answer your first question last, you can check the FTDI by brindging between TX and RX and confirming that anything sent is echoed on your terminal emulator.
Generally it only damages the sanguinololu if 12V are connected in the wrong place, connecting the P2 cable back to front does not normally have this effect however it clearly did in your case. If its 12V in the wrong place (for example with the P2 header put on incorrectly and then the P2 cable plugged in) then more than the ATMEGA could be damaged, its hard to say. I would try with the ATMEGA first and see how you get on.
Regards
Tony