Following the Spanish Garmin support provided to CANTABRO that he details in a different thread, I had the usual 12.30 issues with sensors dropping out and the additional desire to leave 12.10 because of awful battery life, (losing 43% in 1 h 45mins) I did a full factory reset from 12.30, then ignored most of the setup stages. Connected Garmin to computer via USB and downgraded to 11.20. I then went through standard setup but did not connect any sensors. Then I upgraded to 12.30 via Garmin Connect/wireless and then added 3 sensors. (Speed, HR and Cadence, all Ant+ Garmin originals). Just back from 33 mile/1 hour 48 road ride and all was well, no dropouts or attempted reconnections to sensors and.... "only 26%" battery life gone. Far from perfect compared to when the 820 was new less than 3 years ago, but vastly better than with 12.10 and it makes the device usable.
A bit of a pain and convoluted and only 1 ride but thank you Cantabro !!!
