20.26: No altitude change during activity (recorded wrongly as flat with 0m elevation)

Hi everyone, I've run into a problem with my Garmin Forerunner 955 after updating to firmware 20.26. Yesterday, during a race in hilly terrain, the altimeter got stuck at a single value:

The issue was also visible in the altimeter widget. While it was measuring normally before and after the activity, during the race (where other runners' watches measured about 150m of elevation gain), mine showed a flat line.

I ran the race using the Run profile with PacePro enabled, but navigation turned off.

This seems like a newly introduced bug, as I run often and this is a first time I have seen it, right after updating to 20.26.

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0 4679615 3 months ago

just to let you know, the same problem in FR255 in 20.26 version, happens only in runs, during walk it works correctly. In some runs it is fine as well. I did not find any pattern yet

0 2371978 3 months ago

Same problem after 20.29 update 3 days ago. No issue with altimeter app, but problem with altimeter while recording activity(MTB).

On data screen grade=0, ascend=0, descend=0, altitude=same number via all activity. And for example after 1hour of climbing, altitude still shows 600m, but when i cancel activity and check watch face and altimeter app, it shows for example 1000m above the see.

Will be there any update , or somebody have any solution?

I dont care about rubbish buggy forecast, it always shows at least 15 degrees les like it is outside, also dont care about autozoom, which is not working when im using course navigation , but altimeter is a big problem.

0 Balázs 3 months ago in reply to 2371978

I got the suggestion to restart the watch and recalibrate the altimeter.

Not sure whether any of them helped, but I have normal elevation data since then, so you could try that.

0 tomaskafka 3 months ago in reply to 2371978

Unless you ride through tunnels, you can turn on elevation corrections on the connect website, which will replace the altitude from watch with altitude from terrain model

0 2371978 3 months ago in reply to Balázs

I restart than calibrate altimeter but it didnt help. But when i start atcitivity i pause it and than store for further renew and when after 20-30 sec renew activity altimeter start working. Its not a solution of problem , but at least its working.

0 flowing42 3 months ago

Just hit this issue yesterday on a bike ride for the first time. 20.29. Been running since it was released.

0 z-paul 3 months ago in reply to 2371978

I restart than calibrate altimeter but it didnt help. But when i start atcitivity i pause it and than store for further renew and when after 20-30 sec renew activity altimeter start working. Its not a solution of problem , but at least its working.

I also use this solution

0 Thom@s 3 months ago

I observed something similar today (20.29).

It's a combination of altitude and temperature error.

0 6106907 3 months ago in reply to Garmin-Sierra

Hi,

1. No. 3/5 Outdoor runs have had this issue so far.

2. It is normal.

3. Yes

4. Yes

0 z-paul 3 months ago in reply to Garmin-Sierra

Thank you for sharing, everyone. Please answer the following so we can further investigate:

Is your elevation flatlining during every activity?

Does your all day elevation/floors climbed data look normal (outside of activities), or is it also 0/flatlining?

May we have permission to view your Connect account so we can view examples?

May be, if necessary, have permission to reach you via email?

1. No.

2. Yes, normal.

3. Yes.

4. Yes.

I have also one activity with flat elevation on firmware 19.18.