Deleting files from a usb stick may not be good enough for the update. Our Janome Canada tech recommends doing a full format (as opposed to the “quick” option) using windows before installing the update on the usb stick. He also recommends using the smallest usb stick possible. 2 gigabytes is preferred.
The EMB folders etc. should not be on the stick so after formatting with widows in your computer, do not put the stick in the machine to see if it will read it. That automatically puts the folders on the stick