I got to step 7 in the guide:
7) Soon, you’ll see your Kindle detected as a new device.
Your PC shouldn’t be able to find any driver, so let’s help it: point the driver path where you stored Kindle-Fastboot.inf and let the PC load the driver.
But after using mfgtool to load kindle into fastboot mode, my PC doesn't detect any device, or even ask to manually locate a device.
Any idea what to do?