CFLAGS_EXTRA?=-D__SAMD21G18A__ -DUSB_PID_HIGH=0x00 -DUSB_PID_LOW=0x4D -DUSB_VID_LOW=0x41 -DUSB_VID_HIGH=0x23
BUT I am having problems with changing the VID and PID. I can not use Arduino ones as it is not allowed.
It seems like you actually need 2 PIDs, one for the bootloader, and one for normal code execution. Yes, I guess there's a generic CDC inf file for Windows 10, but for anything under, you'll need to create your own that points to usbser.sys. And it's helpful to sign it, especially if distributing it to others. Doing all of that, I was able to successfully change the VID/PID, create a driver, and have my board recognized on a Windows 7 machine. Woot! However, I'm still having trouble with the bootloader. I only have one PID and tried using the same one for both the bootloader and "normal" port, but it's not working. I was able to re-compile and re-burn the bootloader, and although it did enumerate as a COM port, it didn't associate with my board and I wasn't able to re-program through the bootloader.I'm wondering if getting another PID, and adding it to my driver will fix everything. And I'm still curious as to why the bootloader needs to be identified as a completely different USB device.