[Guide] How To Setup And Use Fastboot

What, If Any Other Tutorials Would You Like Me To Make?

  • Tutorial on setting up and using ADB

    Votes: 434 51.5%
  • Creating flashable .zips to be used in recovery

    Votes: 486 57.7%
  • Whatever I want!

    Votes: 195 23.1%
  • Nothing! I make terrible useless guides!

    Votes: 34 4.0%

  • Total voters
    843
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ktmom

Retired Forum Moderator
Apr 22, 2015
5,176
3,387
Deep Space Station K7
Hey !
Love your post it was super helpful. I have one a massive issue i couldn't fix no matter how much I've tried :

I have a PocoPhone F1 with LineageOs & Twrp. I can get into twrp but for whatever reason the touchscreen is not working, so I wanted to flash it with a newer version (to then flash a different rom).
Now the usual method for this is by using fastboot, but fastboot gives me a couple of different errors each time I try use it : "Sending 'recovery' (31068 KB) FAILED (Write to device failed (No such file or directory))" and "Too many links" are the most common ones.
Sometimes it just hangs after I type a command, no error no nothing just a blinking cursor (e.g. I type fastboot reboot and it just sits there).
I don't know if / how I could reflash the recovery. Just loading into it didn't work "fastboot boot recovery.img" "Can't write files to phone". It doesn't list partitions.
I couldn't find a "solo adb" solution since that tool still works. The phone still boots, so it's not a brick.

I'm sorry that I couldn't find a solution on my own :(

I'm not actually clear what fastboot you are using. The Poco threads suggest Minimal ADB Fastboot. Make sure you are using a good cable, or try different ones. And use a USB 2 port not 3.
 

Twiggeh99

New member
Jan 12, 2020
2
0
I'm not actually clear what fastboot you are using. The Poco threads suggest Minimal ADB Fastboot. Make sure you are using a good cable, or try different ones. And use a USB 2 port not 3.

Tried using USB 2 / 3, total potato on both. Going to try this on linux. I used the google provided tools (used them when I first installedtwrp & lineageos). Minimal Tools gave a new error :
target didn't report max-download-size
sending 'recovery' (31068 KB)...
FAILED (command write failed (No error))
finished. total time: 0.003s
 
Last edited:

ktmom

Retired Forum Moderator
Apr 22, 2015
5,176
3,387
Deep Space Station K7
Tried using USB 2 / 3, total potato on both. Going to try this on linux. I used the google provided tools (used them when I first installedtwrp & lineageos). Minimal Tools gave a new error :
target didn't report max-download-size
sending 'recovery' (31068 KB)...
FAILED (command write failed (No error))
finished. total time: 0.003s
I definitely agree with doing this on Linux if you can.
 

fawazahmed0

Senior Member
Jan 31, 2015
337
264
[Tool] Latest ADB Fastboot and USB Driver installer tool for Windows

Hi All, Just posting it here again

I made a tool to install the latest ADB, Fastboot and device specific USB drivers for windows, its very easy to use, just double click the file to start the installation process
you can see it here:
https://xdaforums.com/android/general/tool-adb-fastboot-installer-tool-windows-t3999445

Screenshot:
attachment.php
 
Last edited:
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nay_

Member
Jun 6, 2020
22
10
California
I installed it and keep it updated with the windows package manager, chocolatey

(yes, really)

Code:
choco install adb

now I have adb and fastboot. yay
 

denisalvara

Member
Mar 2, 2020
6
0
One plus 5 Actualización por adb fastboot

Hi All, Just posting it here again

I made a tool to install the latest ADB, Fastboot and device specific USB drivers for windows, its very easy to use, just double click the file to start the installation process
you can see it here:
https://xdaforums.com/android/general/tool-adb-fastboot-installer-tool-windows-t3999445

Screenshot:
attachment.php

Tengo un One Plus 5 que no tiene sistema de partición A/B, solo A (este es el problema mayor), por lo tanto no me ha sido posible actualizar a android 9 o superior, si realizo un borrado completo por fastboot (cuáles serían los comandos adecuados a utilizar) será posible poder actualizar a android 9 sin inconvenientes, sin bloqueos?, porque lo ha intentado de diversas maneras y no ha sido posible, siempre se bloquea y debo restaurar, cuál sería la solución?, gracias por la respuesta, si fuera posible les daría más detalles a través de mi correo electrónico.

I have a One Plus 5 that does not have an A / B partition system, only A (this is the biggest problem), therefore it has not been possible for me to update to android 9 or higher, if I perform a full erase by fastboot (which would be the appropriate commands to use) will it be possible to update to android 9 without problems, without crashes ?, because you have tried it in various ways and it has not been possible, it always crashes and I must restore, what would be the solution ?, thanks for the answer If possible, I would give you more details through my email.
 
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KevMetal

Senior Member
Nov 11, 2016
1,591
623
Amazon Fire TV
Amazon Fire HD 6 and 7
Tengo un One Plus 5 que no tiene sistema de partición A/B, solo A (este es el problema mayor), por lo tanto no me ha sido posible actualizar a android 9 o superior, si realizo un borrado completo por fastboot (cuáles ser

I have a One Plus 5 that does not have an A / B partition system, only A (this is the biggest problem), therefore it has not been possible for me to update to android 9 or higher, if I perform a full erase by fastboot (which ones are
 
Last edited by a moderator:

denisalvara

Member
Mar 2, 2020
6
0
One plus 5 Actualización por adb fastboot

We
Tengo un One Plus 5 que no tiene sistema de partición A/B, solo A (este es el problema mayor), por lo tanto no me ha sido posible actualizar a android 9 o superior, si realizo un borrado completo por fastboot (cuáles ser

Discúlpame pero realmente no entendí la respuesta, le agradezco me pudiera ampliar la solución a el caso, muchas gracias!

Excuse me but I really did not understand the answer, I appreciate you could expand the solution to the case, thank you very much!
 
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Hari150524

Member
Jul 10, 2020
8
0
Vijayawada
Need assistance

Do You need to unlock your bootloader?

Sir, I am using asus zenfone max pro m1, unlocked bootloader and stuck in fastboot mode.
I used fastboot devices and it shown my device then I used erase system cmd. But when I tried to flash recovery it says WRITE PROTECTED. CAN YOU HELP ME, PLEASE.
PLEASE REPLY ME TO MAIL ID : harikonda4@gmail.com
Awaiting for your reply.:):)
 

KevMetal

Senior Member
Nov 11, 2016
1,591
623
Amazon Fire TV
Amazon Fire HD 6 and 7
Sir, I am using asus zenfone max pro m1, unlocked bootloader and stuck in fastboot mode.
I used fastboot devices and it shown my device then I used erase system cmd. But when I tried to flash recovery it says WRITE PROTECTED. CAN YOU HELP ME, PLEASE.
PLEASE REPLY ME TO MAIL ID : harikonda4@gmail.com
Awaiting for your reply.:):)


fastboot oem unlock
fastboot reboot bootloader
fastboot flashing unlock_critical
fastboot flash recovery recovery.img
 

Hari150524

Member
Jul 10, 2020
8
0
Vijayawada
Need assistance

Sir, when I tried oem unlock cmd, it says "fastboot: error: Command failed FAILED (remote: 'unknown command')"
It says samething to other two commands also. Please continue your support...
 

Hari150524

Member
Jul 10, 2020
8
0
Vijayawada
Those commands aren't working for me !!

Sir, when I tried oem unlock cmd, it says "fastboot: error: Command failed FAILED (remote: 'unknown command')"
It says samething to other two commands also. Please continue your support...
 

soyputito

New member
Feb 4, 2021
2
0
my tablet is a block 10.1 it won't let me root it, and it won't let me put it in fastboot mode, it turns off and from there it doesn't come out, my intention is to update android 8.1 to 11 but I'm afraid to briquet it in trble it tells me that it supports the version the version of the trebel project uses vndk what is VNDK? It says that it does not support the root system, that you have to use an A-only operating system. What is an A-only system? which is an ARM 32Y device THAT DOES NOT SUPPORT BACKGROUND UPDATES If it is in your ability to support me with this info to be able to update the android, the steps, what I should know, where can I find out more, a tutorial, it is, what happens is that two tablets have already died and I would not want to what will happen to me with this ... thank you very much
 

xunholyx

Recognized Contributor
Dec 3, 2012
7,906
5,448
Vancouver
Google Pixel 5
Google Pixel 7 Pro
my tablet is a block 10.1 it won't let me root it, and it won't let me put it in fastboot mode, it turns off and from there it doesn't come out, my intention is to update android 8.1 to 11 but I'm afraid to briquet it in trble it tells me that it supports the version the version of the trebel project uses vndk what is VNDK? It says that it does not support the root system, that you have to use an A-only operating system. What is an A-only system? which is an ARM 32Y device THAT DOES NOT SUPPORT BACKGROUND UPDATES If it is in your ability to support me with this info to be able to update the android, the steps, what I should know, where can I find out more, a tutorial, it is, what happens is that two tablets have already died and I would not want to what will happen to me with this ... thank you very much
This is the wrong place to ask these questions. This thread isn't for that. You can probably get some help from here though: https://xdaforums.com/t/help-thread-ask-any-question-noob-friendly.2257421/
 

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  • 178
    Introduction:
    I have found that many people are unaware how to use fastboot, which if you have ever owned an HTC phone or something from the Nexus line you know how important it can be.
    About a year ago I got sick of answering questions about fastboot so I made a guide, but it was device specific. Not too bad but I was constantly giving the links to it for other phones... of course more questions just popped up.
    So here i am making a comprehensive yet easy to follow (I hope) guide on how to set up and use fastboot. I will cover the basics for Windows and Liunx (sorry Apple users, just cant stand the product/company)

    I plan to make a series of guides for XDA-University Thus far there is this guide and:
    [Guide] How To Create Recovery Flashable .zips / update.zips

    First a short explanation:
    Fastboot, like ADB, is a tool to communicate from PC to Android phone. There are times when it is a must to use, and times when it is just helpful.
    ADB is used within your recovery or within your OS, but when you are in bootloader mode and need to communicate with your phone then you need fastboot.

    And you may ask why would i ever need this?
    Well many reasons. Main one is knowledge, learning the ins and outs of fastboot, like learning ADB, can get you out of many jams.
    And if you want to unlock your bootloader this is done through fastboot. Granted HTC's unlock is... well crap, but for a Nexus this is how its done.
    One other reason I have to stress is learning for safety reasons, This is about the safest way possible to flash firmware to your phone (ie Radio, Hboot, Recovery)

    Lastly you may want to know the limitations,
    There are many of course, this isnt JTAG, it will not resurrect a hard brick, but it often save peoples phones from 'soft bricks' and lots of time when know how and when to use it.
    Think of fastboot as the program that takes over when ADB cant be used, it works with firmware more than software.

    So where do i get fastboot? There are a few ways but most often I would recommend getting it from the Android SDK as it is will be up to date.
    or you can use THIS HANDY TOOL created by @shimp208

    I will go over the Download and Installation Process in the Next Post
    Then i will go over useful commands.
    *Just a note, This guide is to always be considered under construction as I plan to continue to make additions such as more commands and pictures
    I will continue to attempt to clarifiy when needed and add what I have missed. I have yet to drop any project or guide I have made on XDA and will help where I can
    As always I encourage questions I may miss something or be vague, it is best to understand fully then not ask.
    84
    Setting up fastboot on Windows and Linux

    What is Fastboot?
    Fastboot is a protocol designed to flash signed/unsigned partitions to android phones directly into the phones flash memory. If you are familiar with ADB think of it in the same way.
    If you're not, just understand it is a tool designed to help flash images such as recoveries, bootloaders, kernels, etc. to your android phone. For the most part you can not use much of fastboot unless you are rooted and have an engineering SPL (Hboot/Bootloader)
    If using a Nexus device you in a sense have an engineering bootloader already so don't need to worry about it like HTC folks need. But Some Nexus lines will have different bootloaders with different capabilities.
    This however is not a tutorial to root your phone so i will not explain this. I will though go over SOME basics as in unlocking your bootloader to allow it to be rooted.
    How do I get fastboot for Windows?

    Fastboot.exe can be downloaded to your computer from Google's SDK found
    HERE download the proper package depending on what system you are using.
    also
    you will need the proper drivers to allow your PC and phone to communicate. You will find these in your devices specific forum or possibly you can use PdaNet


    Okay i got it, whats next?
    After you downloaded the SDK package to your PC see where it is located, somewhere like this for Windows
    C:\android\android-sdk-windows\platform-tools
    Of course put it where you like, just know where fastboot.exe lies

    *If you want to skip the SDK, you can get ADB and Fastboot by themselves with THIS HANDY LITTLE TOOL created by shimp208
    Note: After you have ADB and Fastboot you will may want to finish following this guide to add a path in environmental variables.


    For Windows:
    Although not necessary, but to make it easier i really suggest doing these steps:
    left click the Windows (start) button > right click on computer > choose properties > go to advanced system settings > advanced tab > environmental variables > in the first box (user variables for _____) click new > name it
    > the value is the path from earlier
    C:\android\android-sdk-windows\platform-tools
    (yours may differ from this so double check it!) > in the second box (system variables) find a variable named
    if one doesn't exist make one > double click on it > at the very end of the variable value add the same line as before but with a ; in front of it. like this:
    ;C:\android\android-sdk-windows\platform-tools
    alright click ok and you are done!
    EnviromentalVariables.jpg


    Why did I just do all that?
    Well this allows you to open a command line from anywhere on your computer without changing directories to use fastboot. Pretty much we told your PC that when you type
    or
    into CMD where to find it. As you learn how useful fastboot and adb are this will help a lot as CDing to where you want to be is wasted time.

    So I still don't know what to do or how to do it!
    All right lets start simple, click the windows button and in the search field type
    you will notice a window pop up that looks suspiciously like DOS. View attachment 1980110
    Here you will see a blinking cursor after your directory, lets try this type
    Code:
    fastboot
    a whole bunch of probably unfamiliar stuff should now pop up View attachment 1386065 (for the most part this is a list of commands that can be used in fastboot) if you get something like
    fastboot is not recognized as internal or external command operable program or batch file
    then we need to troubleshoot, but for now i will assume it worked.
    Now try typing
    Code:
    fastboot devices
    ...and nothing will happen, Why? because there isn't a device attached. Make sure you have android debugging turned on in your phone (not really needed for fastboot but you do need for ADB), plug it into your computer and boot into fastboot mode. On many phones hold volume down while powering on, if this wont bring you to bootloader mode then see your device specific forum, if needed choose fastboot. Again try typing
    Code:
    fastboot devices
    this time you should have a list of attached devices, this is displayed as the serial number to each. Being many commands will "do" things to your phone try typing
    Code:
    fastboot reboot
    If your phone is now back and running your existing OS, congratulations! :good: You now at least have fastboot set up and working properly. Now lets try a few things out and see why this can be so helpful!


    How do I get fastboot for Linux?

    To get fastboot installed on your Linux box first download appropriate SDK package From Here
    *Not all Linux distros are the same and I don't consider myself a Linux guru, I will explain what I know about the few distributions I've used but remember if something don't work look up specifics for yours HERE
    After SDK is downloaded extract contents into home folder, maybe in a folder called Android, your choice.
    Now we need to make sure we have the latest java JDK installed found HERE or if you prefer you can get it from the terminal
    Code:
    sudo apt-get update
    sudo apt-get install openjdk-6-jdk
    or if using Ubuntu, the software center. (I have heard people complain about JDK7 so to be safe stick with JDK 6 for now)
    **I have a 64bit machine so I needed the 32bit libraries, you may not need this. If you do run this from terminal
    Code:
    sudo apt-get install ia32-libs
    **As pointed out to me by trevd, if you are using Ubuntu 12.10 or newer you should simply open a terminal and run these two commands
    Code:
    sudo apt-get install android-tools-fastboot
    and
    Code:
    sudo apt-get install android-tools-fastboot
    If you never plan on developing for android or using other tools that come with the SDK
    then this should be all you need. And you may also skip the JDK install. As most people will never attempt to create
    an app or ROM or mod their phone in a way that they would need more than this, these simple commands should suffice.


    Downloading Fastboot
    ummm.. isn't that what I just did? Possibly, but as far as I know ADB, fastboot and everything else in platform-tools wont automatically download with the SDK.
    Other have told me it does, so feel free to navigate to the platform-tools folder and see if you see these applications.
    If you skipped installing the SDK and just installed fastboot and ADB from the command line you can skip down to creating a path. So if you got them, skip this, if you don't, do this:
    From in a terminal type
    Code:
    cd ~/android-sdk-linux/tools
    ./android
    **note depending on what you named the folder the downloaded and extracted SDK is in you may need to change your cd command to something else.
    Now a new window will pop up, Click on "Available Packages" and you will be see two boxes. One is Android Repository and the other is Third-party Add-ons.
    Click on "Android Repository" then click on Install Selected. now click on "Accept All" and then click on the Install button.
    Personally I like downloading all that is possible here, you may have limited space or bandwidth so all you 'need' is the contents of platform-tools.
    If you want to download some API's later go for it, they aren't needed unless you are developing.


    Adding a Path
    Just like in windows changing directories can be brutally annoying so lets add a path. Open a Terminal and type:
    Code:
    nano ~/.bashrc
    or you can use gedit, whatever you have/like to use (sudo gedit ~/.bashrc)
    At the end of this text (or at the begining add the following
    Code:
    Android tools
    export PATH=~/android-sdk-linux/platform-tools:~/android-sdk-linux/tools:$PATH
    **again be sure this is your path (neat trick, find fastboot from within platform-tools, right click on it, go to properties, highlight the location/path and copy/paste this)
    Now click save, this will make so you no longer need to type ./adb all the time
    I have been told a reboot is needed here but I don't think so, just type this into a command line:
    Code:
    source ~/.bashrc


    Drivers? I don't need no stinking drivers!
    True, sorta, but more than likely we will need to add the android rules so your device can communicate with PC. Open a Terminal and Type
    Code:
    gksudo gedit /etc/udev/rules.d/51-android.rules
    now add the following lines:
    Code:
    SUBSYSTEM=="usb", ATTRS{idVendor}=="0bb4", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="0502", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="12d1", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="1004", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="22b8", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="04e8", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="0fce", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="0489", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="18d1", SYMLINK+="android_adb", MODE="0666"
    SUBSYSTEM=="usb", ATTRS{idVendor}=="04e8", MODE="0666", GROUP="plugdev"
    Depending on your device this should be all you need and then some, feel free to check out THIS for the most up to date vendor list.
    View attachment 1980099
    Now for a test!
    So plug your phone into PC via usb, have it in fastboot mode (from within bootloader) and open a new terminal, type:
    Code:
    fastboot devices
    If you see a string of #s and letters then success! :good: you are ready to learn the ins and outs of fastboot!
    69
    Using Fastboot To Unlock Your Bootloader

    Do You need to unlock your bootloader?
    For many phones this is necessary to root, for others it is a poor way to root your phone as you may not have full access.
    Many HTC model phones can be rooted with various exploits, sometimes removing the radio secure flags completely.
    If you have one of these devices than I recommend this, as true radio s-off is far superior to an unlocked bootloader.
    But other phones, including the Nexus line, will be fine just unlocking and do not need to worry, Although some phones like the Nexus One can profit from a new bootloader altogether.
    To begin the rooting process you simply need to unlock your bootloader with this command from a terminal/CMD
    Code:
    fastboot oem unlock
    and the reverse of course is
    Code:
    fastboot oem lock

    Be prepared for a full wipe of your phone when unlocking the bootloader!

    But quickly if you have an HTC and choose to unlock your bootloader to root your phone follow these step:
    Select your phone from the list HERE (you will need to create a log in)
    there will be some legal mumbojumbo to click through (just saying you void your warranty but you knew this!)
    you may need HTC sync found HERE as well as the proper RUU for your phone, the HTCDev site will inform you.
    After which the site will move you through the steps to gain fastboot access, but if you followed my guide above just skip it all.
    next you will need to get the identifier token, this is unique to your device and really just getting probably voids your warranty,
    even if you stopped the guide here. to do so, open terminal/CMD and type
    Code:
    fastboot oem get_identifier_token
    copy and paste this information into the prompt at the bottom of the page. Now wait for an email to get your token....
    once you get the email with the token you can now follow their steps to unlock your bootloader...
    really if at all possible i recommend not to do this method of rooting. But if you do, follow these same next steps that the Nexus devices will be doing...


    Now that your bootloader is unlocked:
    We will flash a custom recovery to your phone, then a custom already rooted ROM. To flash the recovery go to your device specific forum HERE and find the developers section.
    Look for a custom recovery option and consider reading up on it there.
    Different Android phones will have different custom recovery options depending on the developers for it. The most common is ClockworkMod, there are both touch and none touch recovery options.
    some others are TWRP, 4EXT, AmonRa and Cannibal. Find out what your options are, pick one and download it.
    If possible check the MD5Sum, Windows use: THIS and Linux use a terminal and type
    Code:
    md5sum <filename>
    of course replace <filename> with the file name.
    View attachment 1980095
    If you prefer, GTK Hash is a nice program as well.
    Now this should be an image not a zip, so if the extension is .img your good, if its in a .zip or .jar or whatever extract the image.
    Take this image and (for simplistic sake) name it
    **if using windows be sure to pay attention if your file extensions are hidden, don't name it recovery.img.img!
    So be sure your phone is in fastboot mode and connected to PC, open a terminal/cmd in the same location that recovery.img is in
    (cd to that directory or windows users can hold shift > right click in the folder it's in > choose open command here)
    Code:
    fastboot erase recovery
    fastboot flash recovery recovery.img
    **erase recovery is not necessary but i am OCD about wiping...
    now if you get an okay! then your good :good:
    Code:
    sending 'recovery' (4930 KB)...
    OKAY [  0.521s]
    writing 'recovery'...
    OKAY [  0.489s]
    finished. total time: 1.10s
    If not let me know what the output is and ill help you fix it. (I will also make a troubleshooting section in my final post)

    Great! Now Let's Flash a ROM
    In that same developers section for your phone, you should pick out a ROM of your licking. If possible i would suggest an older version of CyanogeMod as these builds tend to be quite stable.
    Also some phones may have newer ROMs requiring you to do various things to your phone. Such as changing radios or bootloaders or other things we haven't gotten to yet.
    So for now try to read the OP of the ROM you like and make sure you meet all requirements.
    So Im not going deep into how to flash a ROM from recovery as this is not part of a fastboot guide.
    But pretty much just pick a ROM and anything else you may need (gapps, kernel, etc) and put on root of SDcard (no other folder)
    Then boot to recovery, wipe all you can (I'll teach you fastboot wiping soon!) and then flash ROM + whatever else you need to and then reboot.

    Another Issue With HTC's Unlocked Bootloaders
    Well if this not yet another reason to try to gain true radio s-off for your phone...
    From with in that ROM that you flashed you also need to unzip and extract the kernel (boot.img) this will need to be flashed through fastboot.
    Once all the above steps are completed reboot into fastboot mode, if your recovery doesn't have a quick way to do so just open a terminal/cmd and type:
    Code:
    adb reboot-bootloader
    from here you will need to then open a terminal/cmd in the same location as that boot.img is and type:
    Code:
    fastboot flash boot boot.img
    If it says okay you are finally done!!! Well done with flashing your first ROM but can you flash a ROM in fastboot? I mean do you need recovery at all?
    There are ways, and ill teach ya in the next post!
    55
    Flashing a ROM through Fastboot

    So Why Do I Need To Do This?
    You don't, normally you would flash a ROM through recovery, but why not have another way? Maybe your recovery partition on your phone is corrupt?
    Maybe you just want to say "I learned something new!" whatever your reason here are the simple steps:

    To start:
    We need to download the ROM of choice to your computer. Once complete find the folder that ROM is in and open terminal/cmd to that directory
    (quickest way for windows; just hold shift and right click within that folder > open command window here) of course make sure your phone is plugged into computer and in fastboot mode.

    Lets see how quick and easy this really is...
    In the command line type:
    Code:
    fastboot devices
    Seeing your serial number means we know all is good
    Now lets type these commands:
    Code:
    fastboot erase system -w
    fastboot erase boot
    fastboot update superawesomerom.zip
    Of course replace <superawesomerom.zip> with the correct file name

    and last but not least:
    Code:
    fastboot reboot

    *Its been a little while since i did this but the phone might automatically reboot after flash so no need to run the reboot command

    As your phone boots into the new ROM, pat yourself on the back...

    A Note on Erasing/Formatting
    You may have noticed earlier that I had you erase your recovery before flashing a new one,
    now here I had you erase system and boot, you may be wondering why.
    I find that a large amount of complaints in developer threads are due to people not properly wiping before a flash.
    Of course there is times when a 'dirty' flash is fine, but if you're ever not sure, wipe as cleanly as possible.
    fastboot allows for about the cleanest of wipes by the way. And each partition can be done separately too.
    Code:
    fastboot erase system
    fastboot erase data
    fastboot erase cache
    can all be done individually, but to do these all in one command
    Code:
    fastboot erase system -w
    If possible I recommend to do these steps before flashing a ROM, and now that you know you can do this all within fastboot mode i suggest to try it out, its quick and painless!
    Don't forget to wipe your kernel too! (fastboot erase boot)

    ~Important~ If your device uses an emulated SD card (as in no removable micro SD but an SD partition on phone)
    Then be careful wiping data/userdata as this will erase all contents of internal SD - you are forewarned!

    What about just flashing a single partition?
    Sure this can be done, hell you can restore a nandroid if you want!
    well first you need to make a nandroid back up (unfortunately fastboot cant make a nandroid for you :crying: ) Put it some where on your computer.
    Personally I only keep maybe 2 or 3 nandroids on my phone's SD card as why waste space. I do however keep almost all my nandroids on my computer separated into different folders for different phones. So my path to a nandroid backup would be something like:
    android/htcg2/nandroids/<nameofnandroid>
    But here's the catch, most newer recoveries do tar backups I believe TWRP uses .win, these can not be flashed in their current form!
    However most older recoveries use yaffs2 format for their backups, these will always work. Pretty much if you get a backup with various partitions as .img you're good to go!
    **Hypothetically speaking here: you installed a new recovery and want to flash a nandroid made in old recovery but the two recoveries used different formats...
    Well you can flash the images with fastboot, then make a new nandroid and you got them back!
    ...Maybe I'm stretching... oh well, here's how to!

    Now the obvious stuff:
    Have phone plugged into PC via USB and in fastboot mode, open terminal/cmd and change directories to that folder where your nandroid is in (or again just hold shift and right click > open command window here if using windows)
    Now in terminal/cmd type:

    Code:
    fastboot devices
    all is good when serial number is displayed, now type:
    Code:
    fastboot erase system -w
    fastboot erase boot
    *This isn't 100% necessary but I'm a firm believer in wiping before any flash, even a backup
    Code:
    fastboot flash userdata data.img
    fastboot flash system system.img
    fastboot flash boot boot.img
    fastboot reboot
    (of course change the image names if needed)
    And you did it! :good: now you are almost a pro at using fastboot!
    keep playing around, you'll get the hang of it and will quickly see that this is one of the best tools in the Android SDK.
    It makes things much faster and easier and in many cases safer than the alternatives. Any questions... feel free to ask!
    Happy Flashing!
    44
    What About Flashing Firmware?

    Flashing any firmware to your phone can be dangerous but if possible the best and safest way is with fastboot.
    Hypothetically you flash a new Hboot through recovery and this Hboot was corrupt in some way, if the flash takes you will have a bricked phone, hard bricked, only JTAG can bring it back.
    But with fastboot you get to input your command to terminal/cmd an see the output, if something goes wrong, just DO NOT REBOOT until you fix the problem.
    And again, checking MD5sums is nice when flashing software but a must when flashing firmware.
    I will again recommend THIS for windows and using the terminal for Linux

    Okay, Time To flash A New Bootloader!
    Some phones will not allow bootloader flashes unless you remove the radio secure flags, if you have a phone like this check the developers thread for a how to.
    To begin, find the appropriate bootloader (sometimes referred to as an Hboot or SPL) for your phone,
    Now download and check MD5sum, have your phone in fastboot mode and open a terminal/cmd in the location your Hboot.img is stored.
    Code:
    fastboot devices
    fastboot flash hboot hboot.img
    and of course replace 'hboot.img' with whatever you titled your image
    **Do not reboot if you see 'sending.... failed' need to see the 'okay!'
    I am not trying to scare you as these instances are so rare, but knowing what to do ahead of time is just common sense.

    Not all devices use the same terminology for partitions, so if the above does not work than consider changing to this command:
    Code:
    fastboot flash bootloader bootloader.img
    Again replacing <bootloader.img> with the name of your image

    Now flashing a new bootloader will more than likely repartition your phone, so from here you probably should flash a new recovery, then flash a new ROM.
    Be prepared to do all this before flashing a new Hboot!

    I'm ready to flash a new radio!
    Flashing a radio can also be dangerous, but again the safest way to do so is within fastboot. So if possible always flash radios in fastboot mode!
    **I am not referring to the FM radio in your car, rather your cellular Radio, you know where you get reception... don't ask me how to add a FM radio to your phone!
    Also know OEMs commonly use baseband and radio as interchangeable terms, for the most part this is the exact same thing

    First things first, know why you are flashing a new Radio. Is it because you have poor reception? Poor data speeds? Poor battery life?
    Yes a new radio can cure all this, but NO ONE can tell you which radio is best for your phone, not even someone living in the same city.
    The best radio for my phone will not for sure be the best for yours, even if you live down the road from me. Don't ask what Radio is best! and only flash a radio meant for your device!

    Now that that's out of the way, lets do the same steps as before:
    Download appropriate radio
    Extract if needed (should be in .img format)
    For simplistic sake name it 'radio.img'
    Plug in phone to PC and open a terminal/cmd in the same location as your radio.img
    Code:
    fastboot devices
    fastboot flash radio radio.img
    fastboot reboot-bootloader
    Again only reboot if all goes well (It will if you follow all direction)
    Upon rebooting your bootloader you will notice your radio version has changed, congrats! You're becoming a pro! :D

    *note, occasionally OEMs package another image called rcdata.img along with a firmware release, if they do I also recommend to flash this along with the radio
    Code:
    fastboot flash rcdata rcdata.img
    **another note, if possible try to match the ril libraries between your ROM and radio, this is device specific and you will need to see your developers thread for this info.
    It is not always possible or necessary to do so, but many do say it help quite a lot
    Flashing a Kernel
    Earlier I went over flashing kernels as part of HTC Unlocked Bootloader Flashing, the process is the same for anyone else as well.
    Locate the Kernel you want to flash
    navigate to the folder it is in (should be in .img format and lets name it boot.img)
    Code:
    fastboot flash boot boot.img

    But lets say you are a developer and have worked on a new kernel for your device, a quick and easy way to test it out may be to fastboot load the kernel:
    Code:
    fastboot erase boot
    fastboot boot kernel ramdisk
    As usual replace file/image names accordingly
    If you do not want to erase the current kernel, just skip erasing.
    But I would just have a working kernel.img handy and erase, this way I know there are no residual effects from previous kernel - choice is yours

    Code:
    fastboot flash:raw boot kernel ramdisk 
    fastboot reboot
    Test it out and see how things go! Good luck! :good:

    As always, if you have questions or comments feel free to leave them here!
    Happy Flashing!