Not all the square terminals have two sides, but in my experience in order to use Bitcoin payments the cashier needs to select the Bitcoin option on their screen before it appears on the payment termi...
This was supposed to be their new rollout today where the customer just selects to pay with BTC regardless of what the cashier does or knows. What you’re talking about was definitely how it worked up until today (supposedly). However, I have not had any luck with it, or heard of anyone that has either.