You mentioned the ST-16 generate a Flight Mode not found message in your PM. The ST-16 is telling you it cannot find the aircraft, which is a pretty common occurrence after a firmware update. The aircraft is no longer bound so it cannot be recognized. A lot of people run into problems here with their ST-16 not finding the aircraft firmware after tapping the Refresh button. The process of tilting the aircraft to get it to enter bind mode does not always work but there is another easier method to place the systems in a mode that will find and bind the firmware by
placing the ST-16 in Team mode. This method has worked perfectly for me with every firmware update for two aircraft. Watch the attached video and follow his process
precisely. Pay particular attention from the time of 0:08:25 onward as it is there it describes entering Team mode.
I do not recommend updating via PC and the GUI as many have encountered problems with this method. I have similar reservations with the use of OTA updates. Using the SD card has
always been effective for both my H's but you have to perform the process correctly by staring with a clear SD card, preferably the card that came with your kit.
Do not place both update files on the card at the same time. Doing so confuses the system. Start with the ST-16 update file. Do not unzip the file as the ST-16 and aircraft will take care of that. If you do open the file before loading it onto the card it will not load to the system. You will get a "file not found" message. Once the ST-16 has received the update file remove the SD card and delete all the files that will be on it. After deleting those files you can load the aircraft and camera file onto the card and place the card in the camera card slot.
The ST-16 will often not recognize cards having more than 32g of storage for the update process. 16g cards work best, which is the storage sized card that came with your H. If the card has too much storage the ST-16 will display a "file not found" message when you try to update. Bear in mind that typically, firmware issues are usually due more to people not fully understanding the process, or trying to use a firmware update to correct problems they induced that were not at all associated with firmware, not because of system problem. When such problems do occur it's best to take a a little time to review procedures that are known to work when the process is followed exactly. Haste has caused a lot of firmware problems as people tend to overlook important steps that are critical to successfully completing the process. Watch the video twice before starting your updates and have the video up and ready for review while you perform the updates.