Where to add an ttyUSBx unbind rule


I connected an FT4232H mini module to the USB host port of my mangOH Green board, and the kernel automatically created 4 extra tty devices (ttyUSB1, ttyUSB2, ttyUSB3 and ttyUSB4).

I want to unbind my ttyUSBx devices to unload the VCP driver, so, that my application can use the D2XX driver functionality.
People suggested me to add following rule to the udev .rules file, but, apparently Legato uses mdev instead of udev.
[alert type=”primary” display=”inline”]ATTRS{idVendor}==”0403″, ATTRS{idProduct}==”6014″, ATTRS{product}==”PRODUCT_NAME”, RUN+=”/bin/sh -c ‘echo $kernel > /sys/bus/usb/drivers/ftdi_sio/unbind’”[/alert]
When I navigate towards /mdev, I only see 2 empty script files (find-touchscreen.sh and usb.sh).
Do I have to add the unbind rule into mdev/usb.sh or into udev/rules.d/50-udev.rules ?