I have a udev rule that work just fine on my Alix (x86) board with voyage linux (debian based).
But with openwrt on the carambola the rule does not match.
I looked at the output from udevadm and all the data look the same and from what I can se it should be a match.

This is the rule:
SUBSYSTEMS=="usb", DRIVERS=="sierra", ATTRS{bInterfaceNumber}=="03", NAME="sierraAT"
SUBSYSTEMS=="usb", DRIVERS=="sierra", ATTRS{bInterfaceNumber}=="04", NAME="sierraPPP"
I use a sierra 8790 module that has 7 serial ports. Port 3 is for AT commands, port 4 is the data port for ppp.
Since I only support one board in each unit this rule makes shure that the name is ok.

Anyone got any idés why it does not work under openwrt??