MicroMod SAMD51 Bootloader UF2 drives hangs up in Windows Explorer

I am trying to load CircuitPython onto my MicroMod SAMD51 (DEV-16791, https://www.sparkfun.com/products/16791) via the UF2 bootloader. I have the processor connected to a MicroMod ATP Carrier Board (DEV-16885), which is connected to my Windows 10 PC via a USB-C-to-USB-A cable. I am able to get the board into bootloader mode, and the UF2 drive pops up in Windows Explorer as MIMBOOT (D:). At that point, if I try to interact with the drive or any of the files in it in any way (dragging-and-dropping a new .uf2 file, right-clicking on any file, right clicking on the drive, etc.) the explorer window freezes up, I get an hourglass of death, and the window title gets the (Not Responding) label of doom. The only way to get the window to respond is to reset the board or pull the USB plug, at which point the UF2 drive unmounts and explorer drops back to the Desktop. I am able to upload code to the SAMD51 using the Arduino IDE and PlatformIO, so I know the bootloader is working, but as far as I can tell the only way to get CircuitPython installed is by dropping the .uf2 file on the bootloader drive, which always results in a freeze.

EDIT: CircuitPython, not MicroPython

Double check the drivers https://learn.sparkfun.com/tutorials/mi … r–drivers and maybe try a different port/cable?