No, unfortunately there was no backup. In the end I was able to write all of the code again in about 3 days. It sucks to have to do that, but at least it was not close to a deadline.
One of my colleagues accidentally did an I-Start on a robot running on a production line at a car factory. Fortunately they were able to get it back up and running with a backup, but it is really horrible user interface design, that there isn't more of a warning when doing I-Start. I think I will contact ABB and ask them to improve this.