[Kindle Fire Android Development] pnguin:
I Found A Solution To Fastboot Timeout

Like many others who have posted their frustrations with the failure of the KFU to complete after getting "stuck" waiting for the device to respond, I was pulling my hair out, and losing my composure. I went days, even weeks, between attempts. I have read this entire thread several times over, trying every trick mentioned. I run several home computers, all with Windows 7, 64 Bit edition. Every one of them did the exact same thing, and failed at exactly the same point. All of the drivers installed correctly, and this was confirmed in the "Device Manager" of the OS.

I have a very old Kindle Fire that was bought for my wife several years back when they first came out. I have never had any problems with rooting it, first using the old ADB method, and later using the KFU of the time. I was running an AOKP Rom version 4.2.2. I had FFF version 1.4A, and TWRP 2.1 for recovery. For whatever reason, I could not get my Kidle to properly flash a JB Rom 4.3. Something always went wrong, so I essentially gave up due to my frustrations. My wife "acquired" my Samsung Galaxy Tab 10.1 for her personal use, so I was never in a rush to figure it out. After doing some research about Fastboot, and the ways to gain access to it, I began to get a grasp on what was happening, and more importantly, what wasn't happening when I tried to use the latest KFU. After some deep thought, and careful considerations, I finally realized that 2 opposing forces were working against each other instead of with each other. Here is the jist of my discovery.........the KFU, when activated, was looking to communicate with the Kindle, and the Kindle wasn't in the mood for conversation. I tried the trick of trying to power the Kindle down, and then reboot so that it would have to door open to talk. Then I realized that 2 things were happening.......first, that the KFU was "timing out" so the reboot wouldn't work because the KFU was no longer in the mood to converse. The Kindle Fire also "times out" when rebooting, only having a small window of time before moving on to full reboot into Android system.

Here is what I did to get them to talk at the same time........first, I booted the Kindle into normal mode, as directed, before running the KFU. I then connected the computer to the Kindle via a generic USB cable. Having already installed the drivers, I then opened the KFU by using the "run" batch file. So far, so good. Everything connected, and I decided that for my needs, I first wanted to update my recovery. I chose the option to install the COTR recovery, and hit "enter". Like every time before, the KFU downloaded the most recent COTR file, and got stuck waiting for my device. At that point, I shut down the KFU and powered down my Kindle. Next, I restarted the KFU but did not make a choice. At nearly the same moment, I rebooted my Kindle Fire. I waited until I saw the fastboot screen come up, then I made the exact same choice in the KFU that I had made before. When I hit the "enter" key, wha-lah, it instantaneously connected, and flashed the file. It only took a few seconds. I got the OK from the KFU, shut it down, and then disconnected my Kindle. I powered it off, then back on, booting into recovery at the fastboot choice. There it was......COTR. I repeated the process by then flashing the latest TWRP on top of the COTR using the same method. Checked back on the Kindle, and there it was......TWRP 2.6.3.1. OK now I have it........just for giggles, I flashed the latest FFF using the same method. I rebooted my Kindle, transferred over the 4.3 Rom and GAPPS file, rebooted into recovery, wiped the heck out of everything a couple of times, then flashed. Now running Jelly Bean 4,3 with no problems, no glitches, and the feeling of having slayed the dragon.

Will this work for others? I am not sure, but it definitely worked for me. What I now realize, is that for whatever reason, the KFU was not rebooting my Kindle, and the timing was not close to right for my application. Perhaps it is a USB cable problem, as I was not using a "factory" cable, a Kernel problem, or even a Rom problem, but for some reason, the Kindle was not rebooting to get to the fastboot mode, therefor, not connecting in the fastboot mode. I hope that this helps others who have had the same sort of problems. Sorry for the long post, but I thought that going step by step and explaining what and why, was important for others to see. Good luck renewing your old Kindle Fire by giving it an Android update. BTW, I went back to TWRP knowing that it's latest version would also handle Kit Kat, Android 4.4. I didn't make that leap on my KF as it is now equal to my Galaxy Tab 10.1, and both of our Galaxy Note 3s. All are running the same OS, so I can easily fix something if it decides to act up. More than 2 weeks since I flashed, and no problems other than re-acquiring my Galaxy Tab.........I am pretty sure that I am fighting a lost cause there.