I'm having the same issue but with my E50 camera. When the camera is straight, it's smooth, from the moment I tilt it down, it's shaking up and down non stop. I always get the camera view but half of the time I can't film or make pictures. Sometimes I get the error message the data link is lost and sometimes the connection is completely lost in flight, also the camera view and get the message the drone will RTH but I can always keep flying the drone. I never fly really far away and am always able to return home safely myself without the RTH function to kick in.
I also have issues with the flight logs. I'm using DroneLogbook as it automatically uploads the flights from the ST16S. The store did a test flight when it arrived with them on the 18th of January '19. A couple of days later I did the upgrade to the new firmware via UpdatePilot. I still didn't fly for a couple of days then as I had to wait for the official registration to be done and the aviation insurance to be arranged (not allowed to fly in Belgium without that). After I did my first 4 flights the day those things were arranged and I connected the ST16S to wifi to upload the flight logs, DroneLogbook uploaded only 3 flights. The day after it also uploaded 3 flights out of 4.
So I started to connect the ST16S to my laptop and copy the logs from there and imported them manually into DroneLogbook, thinking they would be correct. Then I saw one flight was 29 minutes, which was impossible. So I started taking screenshots of my ST16S after each flight to compare the actual flight time. Seems like the logs pulled from the ST16S start counting from the moment the H520 is powered on even though that option is disabled in the menu instead of counting from the moment the motors are armed / take-off until landing. For some reason, DroneLogbook now suddenly does log the correct amount of flights the last two days but still, quit annoying not to be able to fully trust it. Another issue (for me at least) is that since the upgrade, the logs aren't mentioning coordinates anymore but now mention the address (street name).
I also miss the option to see the flight logs (Take-off + Landing time + actual flight time + coordinates) directly on the ST16S after the flight. It's mandatory in Belgium to log this details in our Pilot and RPAS Logbook after each flight, now it's quit cumbersome to get to that information.
I don't know how to revert to a previous firmware but I guess something must have gone wrong during the upgrade or there are several bugs in it. In the UpdatePilot it says all is up to date but the logs in DroneLogbook mention and different firmware (1.4.21).
