Upgrading to the latest Beta of mission planner will not allow upgrading flight controller firmware (Mission Planner 18.104.22.168 Build 1.3.6746.12212)
When going through the process of powering down the flight controller, clicking on OK in mission planner, then power the flight controller up again (over the USB cable), the latest Beta version does not see the flight controller to do the upgrade.
This is not a hardware issue. Used various USB cables that worked previously and two different flight controllers - Cube and pixraptor. First ran into this on a Windows 7 computer (Intel NUC with external powered USB3 hub - Intel NUC USB ports will not power Cube properly for firmware upgrade) and on my main Windows 10 computer which has always worked,
Was stumped, so tried QGroundControl, and it worked flawlessly. First time I used QGroundControl to load firmware. So this ruled out any hardware issues.
Downloaded Mission planner 1.3.55 (build 1.3.6660.28588) and installed after unloading Beta version of Mission planner. Was able to do firmware upgrades.
Downloaded Mission planner 1.3.56 (build 1.3.6672.30243) and installed on top of 1.3.55, and still able to load firmware.
Installed latest Beta (from Mission planner) so was now at 22.214.171.124 (build 1.3.6746.12212) and no longer able to load firmware.
Ran the install program for 1.3.56 again and selected repair. Version came up as 1.3.56 (no .4 at the end), but the last part of the build number was still 12212 - did not note the rest of the build number. Not able to load firmware to the flight controllers.
Did an uninstall of Mission planner, then install of 1.3.56, and was able to load firmware to the flight controllers again.
So does seem to be an issue with the Beta build.