hi. i tried lot of times with fenix5x plus and 2 phones, but i'm not able to update the pedals to 3.8
i also removed the batteries, but i'm still not able to install the update.
I used my iPhone x tp update the pedals and it appeared to simply get stuck. If you are trying to update from your phone, try deleting the Connect app and reinstalling it. Also remove the batteries from both pedals to reset them. After this I found that my Garmin 830 said the update was successful but the iPhone app was showing the pedals stuck at the previous version. Following the procedure I described sorted the problem.