Thank you so much for your postings. I got a similar drawing machine, and there were no instructions to be found about the A1 and C1 code. I just typed that and it solved everything!
During my research I did find that probably you don't need the CH34ser drivers as the newest macs come with it from apple, it may even cause some conflict. Read more here (https://github.com/adrianmihalko/ch340g-ch34g-ch34x-mac-os-x-driver). I would recommend to just trying without manually installing the drivers first.