After having done "A l'Envers" a couple of days ago, I still remembered the moves of the crux, but took some time to work it out again, so there would be less room for doubt when getting there from the start. When an English couple arrived with their kid and dog, Olaf's dog and theirs got into a short fight, hard enough for the English dog to be wounded on its paw and while they were all taking care of it, I used the occasion of the quietness at the roof itself to do a first try in "Bicarburation" from the start. I climbed through the first part quickly and was still feeling better than expected when I arrived at the bat hang rest, so I decided to not stay there too long, chalked up one hand and continued on. To my pleasant surprise, I stuck the crux, stayed calm and focused, and without seemingly too much effort worked my way to the end and topped out.
It took several minutes to realize and sink in that I had just done "Bicarburation".
Unfortunately, the rain showers followed closer and closer to each other and the boulder became too wet to attempt another line. Still more than enough to come back for.