With mwptools one can create and upload missions to INAV based flight controllers.
A Linux operating system required
Connect to the DroneBridge WiFi access point (make sure no other devices are connected at the same time)
Make sure to read the documentation
Download and install mwptools
Run by typing
Go to Edit --> Preferences
Device List. Make sure you separate it with a comma!
In the upper right corner select the added entry and connect