Here’s my preferred method of rooting the Kindle Fire. It’s super simple as long as you follow the instructions. I did this on a Windows machine that’s running Windows 7 Professional 64-bit. Let me preface that rooting your Kindle Fire will void your warranty so proceed with caution! I’m not liable or I won’t be responsible for bricking your Kindle Fire.

You’ll need the Android SDK, Java Development Kit in order to root your Kindle Fire with these steps. The SDK and the JDK downloads may vary depending on your machine. I won’t go into great details about installing the Android SDK and the JDK because it’s pretty self-explanatory. Here goes:

1. Assuming that you have the Android SDK installed already, open the file below in Notepad or a text editor of your choice.

   C:\Users\Your_User_Account\.android\adb_usb.ini

2. Edit the file and type in 0×1949 (Zero, not O) at the last line of the file. It should look like the screen below.Note: I created a new line for each #/comment to make it easier to read.
3. Navigate to where you have the Android SDK installed. It may be in your Program Files or Program Files (x86) directory. I have mine installed on the D:\ drive. With the example shown below, open the file below in Notepad or a text editor of your choice.

   D:\Android\android-sdk\extras\google\usb_driver\android_winusb.inf

4. Insert the following strings in a new line after [Google.NTx86] and [Google.NTamd64]. There should be two instances.

   ;Kindle Fire
   %SingleAdbInterface% = USB_Install, USB\VID_1949&PID_0006
   %CompositeAdbInterface% = USB_Install, USB\VID_1949&PID_0006&MI_01

   Save the file after you’re done.

5. Plug in your Kindle Fire to your computer using a micro-USB to USB cable. Windows will attempt to install the USB drivers for your Kindle Fire. Whether it succeeds or fails from installing the drivers, we’ll load the drivers that we’ve prepared from Step 4.
6. Open Device Manager. I use a keyboard shortcut to get to the Device Manager: Windows + Pause Break key. Then click on the Device Manager on the left hand side. Select the Kindle device  in the Device Manager tree and right click to bring up Properties.
7. Update the driver by selecting the modified android_winusb.inf file from Steps 3 and 4. You’ll get a warning that it may not be safe to install the drivers but we’re going to install it anyway. Click through the prompts to finish updating the driver.
8. Open the command prompt. I’m partial to using keyboard shortcuts so I would press the Windows + R keys and type in:

   cmd

   and then hit Enter. We’ll need to change to the directory of where the Android SDK is installed. On my machine, it’s installed on the D:\ drive so for illustrative purposes:

   cd D:\Android\android-sdk\platform-tools\

   Run the following commands. Press the Enter key after each one.

   adb kill-server

   adb devices

   We’re almost there! If you see your device listed after the previous command, that means you’ve been following every step. Make sure that you see your device listed before proceeding.

9. Download the Kindle Utility Fire. Save this on your Desktop or Downloads folder. Extract its contents.
10. After unzipping the file from the previous step, ensure that your Kindle Fire is still connected to your machine. Run the run.bat file.
11. You should see the following screen:You can choose to install the BurritoRoot (2), which is temporary or opt to permanently root (3). You’ll just need to follow the prompts/ignore some errors. The last thing you’ll need to do is to press any key to complete the process.
12. That’s it! Your Kindle Fire should now be rooted!
13. Bonus step: If you want to install Ice Cream Sandwich (or any other custom ROM), make or restore from a backup on your Kindle Fire, you’ll definitely want to Install latest TWRP Recovery (selection #5).