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[ROOT][WIP] root 6.2.1 / install TWRP / unbrick any ROM

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pokey9000

Senior Member
Apr 17, 2007
767
396
Austin
A while back, I posted about forcing the Fire to boot over USB instead of from the internal memory. This trick requires you to open the back of your Fire, but after that the only tool you need is a pair of tweezers, sharp scissors, bent paperclip, or anything else with a fine point that can short two things together. After that, it's all cake to boot FIREFIREFIRE, then TWRP, then adb in and have your way with the Fire's memory.

Now that 6.2.1 is here ruining our party, it's time to package this up for anyone to use.

As useful as they are now, fastboot cables may not work in the future. They rely on the bootloader to work, and it's possible that a future OTA could disable fastboot.

For the adventurous. This is mostly untested by me, and runs a good risk of fuglifying or permanently breaking your Kindle. If you haven't voided your warranty yet, this will.


Install TWRP over USB

0) You will need a PC with Linux and working adb, the .zip attached to this post, and the installer version of TWRP[/URL]. Also a microUSB cable. And something to short the contact like tweezers or a bent paperclip.

1) Unpack the rekindle .zip and copy TWRP into the directory it creates. Change directories into rekindle/

2) Open a terminal and sudo or su to root. It's easier that way.

3) Unplug the USB or AC adapter if it's plugged into the KF. But have the USB cable's A end plugged into the PC. This is very important.

4) Turn the power completely off. Do a shutdown if actually running Android, or hold the power button until there's no LED or backlight.

5) Pry open the back cover. The iFixit teardown (Google it) gives some ideas on how to do it, but be really careful because it's easy to snap the tabs along the long sides.

6) The power must still be off. If you accidentally powered it back on, turn it back off.

7) Run:

Code:
./usbboot aboot.bin u-boot.bin; ./fastboot boot twrp-blaze-2.0.0RC0.img

This will chain load aboot, FIREFIREFIRE, then TWRP.

8) Short the point shown here to the metal frame around the CPU area using your paperclip or whatever. While keeping it shorted, plug in the USB cable. This will power up the Fire with the CPU in USB boot mode.

9) If it works, you'll see some text fly by in the terminal, and you'll see the yellow triangle hopefully followed by TWRP starting up. You can follow the instructions in the TWRP post on completing the install.


Rooting 6.2.1

***This likely won't work***
There are reports of problems booting after applying this bootimage. Try the TWRP install above and one of the root update.zips instead.

0) You must already be running 6.2.1. Otherwise try a safer method.

1) Get the rooted 6.2.1 bootroot .img from here..

2) Follow the procedure to install TWRP above, but stop before step 7 (the usbboot command). You can skip downloading TWRP.

3) Run this command instead:

Code:
./usbboot aboot.bin u-boot.bin; ./fastboot flash boot 6_2_1rootboot.img

4) Then continue at step 8 until the fastboot flash command finishes.

5) Hold down the power button until it powers off (~15 seconds), and press it again to power it back up.


Windows & OSX support

Currently usbboot is built for Linux only. I had experimented with building it against libusb for Windows and OSX. Unfortunately the window to make the connection before the CPU resets again is about 2 seconds, and Windows takes a lot longer than that to enumerate new USB devices. I don't know about OSX, but I guess a libusb version (usbboot's USB code is Linux-centric) would work fine. Github is here if you want to take a crack at porting it.

Successes? Failures? Smoking hole in the ground that used to be your Kindle? Post here.
 

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Last edited:

dalogrus

Member
Apr 15, 2009
11
3
For the adventurous. This is totally untested as of now, and runs a good risk of fuglifying or permanently breaking your Kindle. If you haven't voided your warranty yet, this will.

0) You will need a PC with Linux, adb and fastboot installed and known working, a copy of the omap4boot for Kindle Fire from this post, a copy of FIREFIREFIRE, the older TWRP 2.0 that doesn't have the FIREFIREFIRE installer (or use the other if you want to install TWRP and FIREFIREFIRE automatically). Also a microUSB cable. And something to short the contact like tweezers or a bent paperclip.

Hi, a silly question here, as you did say one will need a linux machine, but...
Can it be done under Windows 7 64bit?
If so - what software will I need apart from adb shell access, FIREFIREFIRE and TWRP 2.0?
 

mikbe.tk

Member
Nov 28, 2011
15
4
So just to be clear this works with 6.2.1 so would allow a downgrade to 6.2 or a sidegrade to the hacked 6.2.1 image with root enabled?

Sent from my Kindle Fire using xda premium
 
Last edited:

ttabbal

Senior Member
Jul 1, 2009
2,076
723
Samsung Galaxy S21 Ultra
Very cool. I was wondering if this CPU supports leaving it like that but still being able to boot normally, much like FIREFIREFIRE where it starts in fastboot mode, then after a short time, switches to normal boot. There is a hack for the Galaxy S phones that works like this. You short a point on the board, then leave it that way. Now when you boot, it will try to boot from USB, and if that fails, switches over to internal flash. This would be a very nice mod to have.
 

pokey9000

Senior Member
Apr 17, 2007
767
396
Austin
Very cool. I was wondering if this CPU supports leaving it like that but still being able to boot normally, much like FIREFIREFIRE where it starts in fastboot mode, then after a short time, switches to normal boot. There is a hack for the Galaxy S phones that works like this. You short a point on the board, then leave it that way. Now when you boot, it will try to boot from USB, and if that fails, switches over to internal flash. This would be a very nice mod to have.

Yes, it does, but it would take some soldering and more than shorting just one pin. Also we haven't identified all the boot mode pins.
 
Last edited:

pokey9000

Senior Member
Apr 17, 2007
767
396
Austin
Hi, a silly question here, as you did say one will need a linux machine, but...
Can it be done under Windows 7 64bit?
If so - what software will I need apart from adb shell access, FIREFIREFIRE and TWRP 2.0?

Not silly, I've tried to get usbboot to work on Windows when I developed a Nook Color version, but the Windows USB stack sucks. If it were to work, it would piggyback on either libusb or the Google USB driver, either of which have 32 and 64 bit versions. Windows gurus are welcome to lend a hand.
 
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Reactions: dalogrus

mikbe.tk

Member
Nov 28, 2011
15
4
Stuck on Kindle...

I have the 6.2.1 update so tried this.

I followed the instructions but when I `fastboot reboot` the screen goes black. When I power it down manually and then turn it back on it hangs on the initial Kindle boot screen, it never gets to the animated Kindle boot screen.

Code:
# ./usbboot aboot.bin u-boot.bin; fastboot flash boot 6_2_1rootboot.img
?
waiting for OMAP44xx device...
sending 2ndstage to target...
waiting for 2ndstage response...
sending image to target...
< waiting for device >
sending 'boot' (3234 KB)...
OKAY [  0.814s]
writing 'boot'...
OKAY [  1.155s]
finished. total time: 1.969s
MintBookPro kindle # fastboot reboot
rebooting...

finished. total time: 0.001s
#

I noticed the fastboot command didn't have ./ in front of it so tried that with the same results, it just hung on the Kindle boot screen.

Out of curiosity I tried the TWRP image and that worked so I was able to install the full rooted 6.2.1 (not just the boot image) from TWRP and now I have 6.2.1 rooted.

So I don't think there was anything wrong with your app, that seemed to work fine, but the plain 6.2.1 boot image seems not to work. Which isn't your issue but anyone that tries this needs to be aware of it.
 

kfuller

Member
Dec 6, 2011
19
3
Great work pokey9000! Very interesting what you are doing.

A couple of questions if you can spare the time.
1) What bootmode is it that shorting the pin enables?
2) As I have a factory cable, would this do the same without popping the case?

Also, and this is off topic and possibly already asked and answered, but I'm curious of your thoughts of the possibility to just select boot from usb on power up from the device, maybe through a utility such as TWRP or some other. Seems that if that could be done, one could greatly increase the size of storage, effectively circumventing the current internal storage limitation. And since the usb is removable and rewritable, you could revert to an earlier version archived on a pc if any updates get pushed that break something.
 

pokey9000

Senior Member
Apr 17, 2007
767
396
Austin
I have the 6.2.1 update so tried this.

I followed the instructions but when I `fastboot reboot` the screen goes black. When I power it down manually and then turn it back on it hangs on the initial Kindle boot screen, it never gets to the animated Kindle boot screen.

Corrected my directions to hard power off. Reason is that the boot mode gets detected on cold reset, and the reboot warm resets and so doesn't detect the new bootmode. I suppose we could add something to override the boot mode when you call reboot if it detects that USB is the boot device. Code is already there to do something similar with bootmode 4003.

I noticed the fastboot command didn't have ./ in front of it so tried that with the same results, it just hung on the Kindle boot screen.

My bad, fixed.

Out of curiosity I tried the TWRP image and that worked so I was able to install the full rooted 6.2.1 (not just the boot image) from TWRP and now I have 6.2.1 rooted.

So I don't think there was anything wrong with your app, that seemed to work fine, but the plain 6.2.1 boot image seems not to work. Which isn't your issue but anyone that tries this needs to be aware of it.

Don't know about this, these directions were created w/o a Fire in my possession. I'll make a note in the OP to try the TWRP method.
 

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    A while back, I posted about forcing the Fire to boot over USB instead of from the internal memory. This trick requires you to open the back of your Fire, but after that the only tool you need is a pair of tweezers, sharp scissors, bent paperclip, or anything else with a fine point that can short two things together. After that, it's all cake to boot FIREFIREFIRE, then TWRP, then adb in and have your way with the Fire's memory.

    Now that 6.2.1 is here ruining our party, it's time to package this up for anyone to use.

    As useful as they are now, fastboot cables may not work in the future. They rely on the bootloader to work, and it's possible that a future OTA could disable fastboot.

    For the adventurous. This is mostly untested by me, and runs a good risk of fuglifying or permanently breaking your Kindle. If you haven't voided your warranty yet, this will.


    Install TWRP over USB

    0) You will need a PC with Linux and working adb, the .zip attached to this post, and the installer version of TWRP[/URL]. Also a microUSB cable. And something to short the contact like tweezers or a bent paperclip.

    1) Unpack the rekindle .zip and copy TWRP into the directory it creates. Change directories into rekindle/

    2) Open a terminal and sudo or su to root. It's easier that way.

    3) Unplug the USB or AC adapter if it's plugged into the KF. But have the USB cable's A end plugged into the PC. This is very important.

    4) Turn the power completely off. Do a shutdown if actually running Android, or hold the power button until there's no LED or backlight.

    5) Pry open the back cover. The iFixit teardown (Google it) gives some ideas on how to do it, but be really careful because it's easy to snap the tabs along the long sides.

    6) The power must still be off. If you accidentally powered it back on, turn it back off.

    7) Run:

    Code:
    ./usbboot aboot.bin u-boot.bin; ./fastboot boot twrp-blaze-2.0.0RC0.img

    This will chain load aboot, FIREFIREFIRE, then TWRP.

    8) Short the point shown here to the metal frame around the CPU area using your paperclip or whatever. While keeping it shorted, plug in the USB cable. This will power up the Fire with the CPU in USB boot mode.

    9) If it works, you'll see some text fly by in the terminal, and you'll see the yellow triangle hopefully followed by TWRP starting up. You can follow the instructions in the TWRP post on completing the install.


    Rooting 6.2.1

    ***This likely won't work***
    There are reports of problems booting after applying this bootimage. Try the TWRP install above and one of the root update.zips instead.

    0) You must already be running 6.2.1. Otherwise try a safer method.

    1) Get the rooted 6.2.1 bootroot .img from here..

    2) Follow the procedure to install TWRP above, but stop before step 7 (the usbboot command). You can skip downloading TWRP.

    3) Run this command instead:

    Code:
    ./usbboot aboot.bin u-boot.bin; ./fastboot flash boot 6_2_1rootboot.img

    4) Then continue at step 8 until the fastboot flash command finishes.

    5) Hold down the power button until it powers off (~15 seconds), and press it again to power it back up.


    Windows & OSX support

    Currently usbboot is built for Linux only. I had experimented with building it against libusb for Windows and OSX. Unfortunately the window to make the connection before the CPU resets again is about 2 seconds, and Windows takes a lot longer than that to enumerate new USB devices. I don't know about OSX, but I guess a libusb version (usbboot's USB code is Linux-centric) would work fine. Github is here if you want to take a crack at porting it.

    Successes? Failures? Smoking hole in the ground that used to be your Kindle? Post here.
    4
    how about a quick run down on how to do this now? :p I have some time and really want to mess with this thing :cool:

    Moved into the main post.
    4
    EDIT
    1st borked usb ports, then i got it to work :)

    !CONFIRMED WORKING!
    2
    Cool! Thanks man, the whole community thanks you. Any chance of a youtube tutorial? I think many of us will need it. Haha
    1
    insted of opening the difficult case what about drilling a small hole that allows a tool to get tru and short?
    Does anyone have a case open to take precise measurements?

    Bad idea. It's too easy to create an ESD and ruin some component. Then you would have to deal with dust, dirt, and possibly even moisture getting in. It's best to just open the case.

    Oh, and use a safety pin for the short ;)

    Just thought I'd mention (in case someone hasn't) guitar picks are particularly helpful when opening cases.