Continued software issues with Edge 820 (12.50)

I'm having the same problem as I had on 12.30 with 12.50. Randomly during a ride my speed and the time just stop. I have to pause the activity and then power cycle the 820 to get it working again. I didn't experience the issue in 12.40.  How do I downgrade to 12.40 ?

I'm feeling the urge to jump ship to the Hammerhead Karoo