#fernvale-osx

Fernvale (Mediatek) OSX codeless drivers. The device shows up at as /dev/tty.usbmodem1410 and /dev/cu.usbmodem1410 for me. You MUST use the /dev/cu.usbmodem1410 interface when loading fernly

##install You need to disable signing which became mandatory at some point recently https://apple.stackexchange.com/questions/163059/how-can-i-disable-kext-signing-in-mac-os-x-10-10-yosemite

sudo nvram boot-args=kext-dev-mode=1

and reboot.

In a terminal

sudo cp -R fernvale.kext /System/Library/Extensions/
sudo chown root:wheel /System/Library/Extensions/fernvale.kext

##info

Fernvale wouldn’t create a /dev/tty for me under OSX Yosemite.

dmesg reported:

AppleUSBCDCACMData: Version number - 4.2.1b5, Input buffers 8, Output buffers 16
AppleUSBCDC: Version number - 4.2.1b5

At first I hoped to make a codeless kext but I'm was under the impression thats impossible for serial devices.

I was able to take the darwin sources apart, now found as fernvale-osx enable logging to find this much:

Jan 24 03:14:48 jacob-2 kernel[0]: USB (XHCI Root Hub USB 2.0 Simulation):Port 1 on bus 0xa connected or disconnected: portSC(0xe0206e1)
Jan 24 03:14:49 jacob-2 kernel[0]: 0        0 AppleUSBCDCECMData: start - Find CDC driver for ECM data interface failed
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: start
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: initStructure
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: findCDCDriverAD
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000 0 0xffffff8035b43a00 AppleUSBCDCACMData: findCDCDriverAD - CDC driver candidate
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000 0 0xffffff8035b43a00 AppleUSBCDCACMData: findCDCDriverAD - Found our CDC driver
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: start: Found the CDC device driver
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        8 AppleUSBCDCACMData: start - Number of input buffers requested
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0       10 AppleUSBCDCACMData: start - Number of output buffers requested
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        8       10 AppleUSBCDCACMData: start - Buffer pools (input, output)
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000 0 0xffffff8035861400 AppleUSBCDCACMData: createSerialStream
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: createSerialStream - NON WAN CDC Device
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: getPortNameForInterface
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: findControlDriverAD
Jan 24 03:14:49 jacob-2 kernel[0]: e6005000        0        0 AppleUSBCDCACMData: findControlDriverAD - No AppleUSBCDCACMControl drivers found (iterator)

After a weekend of testing and studying, with credit to OS X and iOS Kernel Programming by Ole Henry Halvorsen I was actually able to alter the plist to match against the Mediatek data/comm interface while making no additional source code changes. One theory I currently have is that the Mediatek chip has its data/comm interface on 0 instead of 1 where Arduino/etc seem to have it and that whats throwing off the default matching.