I also have an RTL / Loiter problem that I can’t get past.
A GPS module with NMEA protocol is used here.
FLIGHT STABILIZE OK, GPS is OK and the position of the Glider is displayed.
In MODE RTL or Loiter, the Glider shows no reaction and just continues to fly straight ahead.
Can you share a .bin log of a flight when you tried RTL or Loiter? How does the plane fly in FBWA? How are you changing modes? Do you see the mode change on the HUD?
As far as I can see, the information from the NMEA protocols (GGA and RMC) is only evaluated for position detection.
A different NMEA protocol is probably used for flight direction (TRK) and flight speed, hence no RTL / Loiter function.
I just need to know which protocol is used to calculate for TRK and Speed?