Planned to have a 1h-ride during lunch break and just lost 1h45 troubleshooting what’s wrong (and still not fixed) after updating to 1.3.17… Resistance seems all wrong as even at 120rpm on the biggest gear (50x11!) I’m doing 60W… Seems to be linked to spindown calibration although several calibrations were done using both Wahoo app and Zwift on my computer with no help.
(I understood that 1.3.17 is supposedly bringing auto calibration therefore Zwift should not display the option anymore? Well it does here, for what it’s worth).
Of course, no option for firmware rollback. Thanks Wahoo, don’t know when my next Zwift session will be!
EDIT: after 2h30 (my longest lunch break ever, and still haven’t had lunch…) it seems I managed to fix it.
1/ I installed an older version of the Wahoo Android app from apkmirror (1.63.0.45 to be precise) and used the hidden menu to re-apply firmware 1.3.17 (procedure kindly provided by @Tom_Hagler here: Wahoo Kickr Core 1.1.1 firmware issues - #5 by Tom_Hagler) (NOTE: cannot be done from more recent versions of the app)
2/ I immediately reset the KICKR CORE by unplugging the power cord for 30s as recommended on Wahoo’s website then re-plugging it (https://support.wahoofitness.com/hc/en-us/articles/13354735432850)
3/ I used the same hidden menu from the old Wahoo Android app (NOTE: can be done from more modern versions of the app as well) to perform a factory spindown (not the same as a “standard” spindown as this one requests warming up the CORE for 3mins before running you through 2 consecutive spindowns). I got some results at then end: 1st spindown was something around 27s, the 2nd one around 2.9s… So yeah, the firmware upgrade definitely ruined the spindown such that a standard calibration (several actually) did not solve the issue…
Quickly had a 2-min workout (ERG ON) and a 1-min paced group ride and it seemed fine, will have to give it a longer try later though.
Obviously I’m not sure all these steps were necessary and maybe a factory spindown from the latest Wahoo Android app would have been enough, but at least you have all the details of which seems to have worked for me.