Yes, ... your firmware is 5 years old... there is a tremendous difference, especially in how the internal scripts are handled... in 9.2 many of the scripts for the controller are called from server at GUI and NOT loaded into controller memory...iinternet connection must be active and good, especially when accessing the controller GUI. If there are any issues with conteroller connecting to server - delay or timeouts - it may not complete validation or script access. That connection is not the same as 'data send'.
If you haven't already, browse through
https://forum.blitzortung.org/showthread.php?tid=2584 ...you'll absolutely need to know changes and 'bugs' affecting current firmware 9.2 once successful.
.... initiate a discussion on the BT forum in the internal section, and continue troubleshooting from there, rather than here publicly.make sure your sref back to your station number (973), which you didn't include here.
You said you'd reset? Did you do a cold restart or just a 'reset'...???If I remember correctly, 7.4
will not update from the web, you shouyld down load, and load locally. I may be in error on that.
Try an intermediate firmwaye, such as 8.4, before going to 9.2.You may have to try a DFU method rather than direct upload.
Good Luck!