Thanks for the answer. All I did was pull DRXD and DTXD pins from micro to females headers pins so I can use my FTDI cable, no rs232 level translator here .After that I have connected cable TX to header RX, cable RX to header TX and also I read that I should connect cable ground to pcb ground which I'm doing. I have tried to flash around 40 times!! and only two in between I was able to pull off samba but my nerves betrayed me and I upload Netduino gen 1 bootloader which works over USB by default and not Mini variant using UART. Then, I have tried to flash it many times and cannot longer get sam-ba to work. I guess that chip could damage but I check voltage and continuity and everything is perfect,also chip is not getting hot indicating some short.I ordered couple more to replace but in the meanwhile I'm deeply lost here since it should work without issues.