Please tell me what you need to know and I will write it up. On Linux or a Mac the upgrade disk disappears completely every time it checks for new files. (about every second or two) This interrupts copies, or truncates them, and umounts the drive about as fast as the OS can mount it. This makes it so that you can’t copy anything reliably. I even tried to write a script to detect the disk had reappears and then did an ordered copy of the files, but that failed as well. Windows seems to tolerate the disk disappearing for a moment, but Linux and Mac os treat it as if the drive was unplugged while active. So the experience on Windows is good, but it is unusable on Mac os or Linux, even from a program trying to interact with it.
Is this what you need or is it something else? I am willing to help, but it is hard to know what someone doesn’t know. If I were going to fix it, I would change the embedded code to wait for a button press before disconnecting to check for new/changed files. That way you could succeed on copying the files on, before the system sees the disk go away as it now does.