I’m sorry to say that as Horizon was not able to find any solution I returned the buy and asked for a refund. Now I have a Stages SB20 and I can tell you only these things:
GR7 power is only estimated and it’s always wrong, it give away almost 70W more than real. (bike estimates power putting together brake position and cadence, but it is really approximate, because brake position will not be never precise and repeatable)
As the power is only estimated you cannot really win any competition, because in official races you will be always disqualified.
It seems that bike does not support software upgrades so these issues cannot be easily solved except by replacing the card.
So you have the vantage to do less effort with good results if compared to others that run with certified bikes but you are running, at least for Zwift use, on a kind of toy.
The only thing you can do for cadence is to use an external sensor that can be placed on one shoe, unfortunately the pedal arms can contain easily a sensor, I’ve measured and there is no space.
You could still transform radic lly your bike buying two power meter pedals, but it will cost almost 600 Euro and I don’t know if it’s really worth for the price, at that point you can spend some money to have a bike that is working also in erg mode.
That’s my 2 cents.
GR7 was mechanically a good bike and I’m still asking myself why Horizon still don’t have anything specific for Zwift, because they have really all the potentiality.