It does work on Pixhawk 1. Have you ever seen it work in any form on the Pixhawk 1, or is still a starting problem there? (Also when in doubt I just swap the pins between Rx-Tx just incase someone labeled something wrong, which has been more common then I’d have expected.
You definitely want to be using UBX instead of NMEA. The NMEA messages do not give us as much information as the UBX ones do, which causes you to feed a bit worse information into the EKF, as well as the fact that if
GPS_AUTO_CONFIG is set to 1 we will fully enable all the required messages (and turn others off to save processing time and bandwidth on both sides), where as you are responsible for culling the messages to the correct set with NMEA.
The baud rate parameters on the Serial ports only have an effect on a limited number of the GPS drivers. The ublox (and NMEA) driver do auto bauding, which means they test a predefined list of baud rates and cycle through them automatically. This means changing/setting the
SERIALx_BAUD parameter has no impact, even though it seems like it would.