Edge 840 27.13 firmware file.

I don't think so, 29.22 (official) gives me 56m total ascent, 27.13 gave 160m, strava correction is 168m. And i can see all my rides with newer fw-s since 27.13 have significantly less ascent, but now with 29.22 is abnormal.

then something wrong with your unit, is the baro's hole clean on the bottom near to the mount? did you ride in rain in the past days? the 29.22 gives totally the same TAs as the older stable (28 and prior, i have thousand of comparisons , i ride daily 2-4hs on different type of terrains)

but can You send me a FIT file (in private message) where You got this 160m with 27.13 and now it is less? 

If it's wrong something, then the update broke it. Baro hole is clean and dry. Similar thing happened to me with Edge 530 too, every newer update than 9.10 messed ascent and elevation. Downgrading to 9.10 fixed it. I can send you fit file later.

okie. 

But just in short: Not always the highest Total Ascent number is the true one, and there are some type of terrains (usually pancake flats or contains lots of flats) where the x30 (and x40) series calculated really high (false) numbers comparing to the real , valid numbers.

so , pls check these: (orange arrow for the baro's hole, green arrow for the right assemly direction ,avoiding to install back upside down)

i think this hole got dirty (moisure in this hole or around it through the summer) and this is why the raw datas in the fit file got flatter and flatter elevation profile (it is a sign of the moisure in this hole) and not the calculation method or something else the problem. so unscrew that 2 tiny screws, blow out that hole multiple time, install back and re-try.

one more question, do you use any rubber case on it or what kind of mount do you use and where on the bike (stem, front mount, etc)

i have checked that hole multiple times and i haven't really ridden in wet conditions. But will check again to be sure, i don't have case for my computer and my computer sits on stem.

the high humidity is enough for that, or the stem position can collect and hold the sweat easier , harder to dry out comparing to a front mount for example.

I will check that when i get home. Thanks for your help!