USB-serial driver https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers?tab=downloads
To update the firmware, you will need a
USB to Serial Converter(PR55-68 or any USB to serial) Windows PC
Note: if the file name has any special char, please remove it
How to put in program mode
Start the programming utility.
Select the correct COM port.
Select the updated file.
Click update immediately.
Press and release the RST button
Once the firmware update is finished, the device will reboot
command to use serial python update tool --
python ncd_py_bootloader_v2.py COM3 ./Upgrade.ncd 240