Here's what I think I learned:
- Don't expect your Cadence Sensor to update.... Garmin says it does not require software updates: https://support.garmin.com/en-US/?faq=PzqFFaxR7l6NZtF8lTlXj9
- Note that my Cadence Sensor self identifies in the Garmin Edge as a '20' not a '2'... Garmin should be more respectful of this
- I think the Firmware update/connect fail message for the Speed Sensor is errant in some cases (an update firmware flaw)
- I too received the fail notification, but then I interrogated the sensor in my Garmin Edge and there it registered as current to the 4.0 update
- In my case it appears the install tool throws a false error notification as my Edge clearly shows the Speed Sensor as Firmware 4.0 updated
- Not sure this will help anyone but for me it was somewhat reassuring to see that my Edge 1030 Plus at least says the Speed Sensor is updated to 4.0 despite the annoying fail message that persists..