Hi Hermanus,
While my problem was on a different board, perhaps what I figured out will help you. The problem looks to be caused by the seeeduino board library V1.8.0. It breaks the SAMD on my Odyssey. V1.7.9 flashes fine. Per ansonhe97 I have ordered the parts to reflash the bootloader. Hopefully I am able to reflash the bootloader.
Best of luck to you.
Cameron