Give it try on Windows … just to be sure it is not the boards. All Artemis boards have the Ambiq loader or the SVL loader. In case of the SVL loader, you could try a lower speed. On my Ubuntu 460800 is the MAX. Above that it will fail 100% of the time. So maybe also try at 230400 or lower. If the SVL loader is on the board it will detect the speed automatically.