A friend of mine bought a Kindle Fire HD 7" and would like to root it so he can install the Google Play store and actually have some useful apps on it. He gave it to me to try that task. I acquired everything I need to be able to install CM11 on the tablet and attempted it initially from a Windows 8.1 machine at my office. Had a heck of a time with the driver, but even with the driver installed, the device just wasn't recognized.
i thought maybe it's the cable, maybe it's the operating system... So I took it home and used a different USB cable and used my Linux laptop, which doesn't need any special drivers and can do adb natively. The tablet is not recognized in Linux either. I tried issuing the lsusb command to see if anything registered as being plugged into the USB bus, and I get the same list with the tablet plugged or unplugged.
Any ideas? Is a proprietary cable required? Is there something I'm missing in the tablet that needs to be turned on? In both cases, the tablet was charging from the USB connection, so I assume the cable may be fine.