My take on how to access the serial port header with a generic (your wire colors may be different!)
CA-42 cable.
It allows you to see the boot process beyond "Starting kernel ...", where nc stops. A great aid in troubleshooting boot issues!
1) Bend the pins and drill appropriate holes
2) Check alignment
3) Insert CA-42 cable with female D-SUB connectors attached
4) Done. See attached .jpg's
HTH, Jim