How to unlock the bootloader of an Android Phone

Written By: Sebastian
  • Comments: 31
How to unlock the bootloader of an Android Phone

Difficulty

Moderate

Steps

7

Time Required

2 minutes - 3 hours

Introduction

Unlocking the Bootloader allows you to install custom firmware on your Android phone and gives you full access privileges to make modifications to the phone. Such modifications could involve changing some of the pre-loaded software or could even include replacing the entire operating system.

Some bootloaders are not locked at all, some can be unlocked using a standard fastboot command, others need an unlock code from the manufacturer. There are also phones that do not include an unlocking method at all and can only be unlocked through a software exploit. These locked down devices will typically stem from a carrier deal.

In this guide I´ll only be covering the unlocking of bootloaders with the standard fastboot command.

Warnings

  • Unlocking the bootloader will reset your phone, so make sure you have all your data backed up!
  • This might void your warranty with some manufacturers.
  • An unlocked bootloader will trip the Play Integrity API (formerly SafetyNet Attestation API) which can cause some services like GPay to stop working.
  • This will make your device vulnerable against hackers with physical access to your device, so don´t do this to a device you intend to carry state/company secrets on.

Additional information

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    • First, we need to find the Build Number.

    • Usually you can find it under About Phone > Build Number or System > About Phone > Build Number, but since it varies from device to device using the search function is usually the easiest way.

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    • Now you just need to tap the Build number repeatedly, until you get a confirmation message saying "You are now a developer!". I already enabled developer options on my device, so I don’t need to do it again.

    • You might be prompted to enter your lock screen password, if you have one set up.

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    • In the developer options, find the OEM unlocking option and enable it.

    • You might be prompted to enter your lock screen password, if you have one set up.

    I can't enable the OEM on my phone

    Ibsan Furgassa -

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    • In the developer options, find the USB debugging option and enable it.

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    • Plug your phone into your computer via a USB-C to USB-A Cable.

    • If you have a bad cable you might encounter some problems. Some older devices also dislike USB 3 in fastboot mode.

    • Pull down the notification shade and select Charging this device via USB.

    • Select the option File transfer/Android Auto.

    • On some older devices this option might be called MTP instead.

    Well that takes care of that cuz I don't have a regular PC but I will save these directions since Someone is donating a Chromebook to me, I went back to consumer cellular after they went with ATT instead of TMobile also & ATT installed software and what looks like bootloader and something about binding? Permissions say NO or NA but they were allowed to do this anyway! I'm furious

    deb patterson -

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    • Open the terminal application on your computer with the SDK Platform Tools installed and enter adb devices

    • This should trigger a popup on your device. Make sure to have the checkmark ticked and click Allow.

    • I haven’t added the platform-tools-folder to PATH. That’s why I need to open my terminal window in the platform-tools-folder and enter .\ as a prefix to my commands.

    • You can run the command again to check if it worked. It should now say device instead of unauthorized.

    PS C:\Users\ADMIN> adb reboot bootloader

    adb : The term 'adb' is not recognized as the name of a cmdlet, function,

    script file, or operable program. Check the spelling of the name, or if a

    path was included, verify that the path is correct and try again.

    At line:1 char:1

    + adb reboot bootloader

    + ~~~

    + CategoryInfo : ObjectNotFound: (adb:String) [], CommandNotF

    oundException

    + FullyQualifiedErrorId : CommandNotFoundException

    help me pls how do I do that

    Lê Minh Khôi -

    Since you probably haven't "installed" the platform tools, you'd have to use the terminal in the folder you downloaded. You could do that by first running the command cd C:\[location of the folder]\platform-tools first and adding a .\ in front of every subsequent command, like I do in the guide images. Alternatively, if you have a current version of Windows 10 or 11, you can actually install the platform tools via the Microsoft Store by running winget install --id=Google.PlatformTools -e

    Sebastian -

    Okay, so how do I get into the terminal mode on my laptop?

    ArlinaEinstein -

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    • Enter the command adb reboot bootloader

    • Wait a couple seconds until your device rebooted into the bootloader, then enter the command fastboot flashing unlock

    • Some devices might use the command fastboot oem unlock instead.

    • If you receive an error message along the lines of FAILED (remote: 'Failed to unlock, decrypt failed!'), your phone has a locked bootloader and needs an unlock code from the manufacturer.

    • You should now see a prompt similar to the one shown in the picture. Use the volume rocker to choose the Unlock the bootloader-option and confirm by pressing the power button.

    Hw long step take

    Josh Chibs -

    for me it says what can i do? and nothing happens

    C:\Windows\System32>fastboot flashing unlock

    < waiting for any device >

    Murathan Kilic -

    That means that it can't find your device. Have you made sure it's properly connected? Maybe a loose connection? If you are using a USB 3 cable, try using a USB 2 cable instead. USB 3 cables can sometimes cause problems. Sometimes you need to install a USB driver for your device as well, but if ADB worked Fastboot should typically work as well without installing any additional drivers.

    Sebastian -

    I get stuck at the fastboot flashing unlock/ fastboot oem unlock step.

    When i use adb reboot bootloader the phone screen does turn on, but show nothing... is that right?

    Also is it ok that my phone disconnects briefly after the adb line?

    oajk -

    The brief disconnect is normal, since the device is rebooting, but it should show a rudimentary interface instead of just showing a blank screen. Doesfastboot device report a device even though the screen shows nothing? If so, maybe you can continue anyways.

    Sebastian -

    I keep getting: "remote: 'the command you input is restricted on locked hw'" What do I do?

    The RadioDemon -

    Are you trying to unlock an Amazon Fire device? I don't really have much experience with more locked down devices, you might find someone who can help you on the XDA Forum or Reddit.

    Sebastian -

    I need help and the command works fine but my phone turns off to show me the menu problem is that my automatic mode is charging only and not file transfer


    Le pro -

    Que puedo hacer si no detecta las teclas de volumen?

    Como le doy en 'yes'?!

    Para aceptar el desbloqueo

    A VTRX -

Conclusion

To relock your bootloader just run the command fastboot flashing lock

Only lock your bootloader while running stock firmware, or else your device will be bricked!

Author

Sebastian

Member since: 19/08/18

19300 Reputation

17 comments

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File Rehab -

I'm using a Nokia G60 I was offered.

When I try "fastboot oem unlock" I get:

FAILED (remote: 'Failed to unlock, decrypt failed!')

Please update the guide for such cases.

Thank you

Bruno -

As far as I know, Nokia phones need an unlock code from the manufacturer. I don't have much experience with this, so I suggest you ask/search around on forums like xda developers or reddit. It might even help to directly ask the Nokia support for help. Depending on who you end up with they might even help you out.

Sebastian -

did it work with any realme device?

ëĺäžäžÿ -

Realme requires you to run an app beforehand, but the rest of the process should be pretty similar.

Sebastian -

I didn't complete this step by step but it seems like a pretty well put together and quite possibly useful so I think you deserve the 30 points anyway. going to save this guy and check back in after Ive tried it out

Dago Gomez -

Device does nothing once it restarts to enter bootloader. What to do? No other key combination works too. Device is Coradir C01.

Coco Mark -

Don't waste time, if the hardware has locked oem and that oem unlock is greyed out, you cannot unlock it. You'll need a specific code or unlocking tool from hardware manufacturer to unlock any tablet that has the boatloader locked. there is no other way around it. only a few tablets can load new firmware that was not original. nexus 7 you can load android on it. most tablets you need manufacturers tool to communicate with the software in the chip level. you can remove the chip and put chip in it but that is too much work the tablet is stuck with the OEM software. and you cannot even upgrade it. contact the manufacturer. only pixel cell phones or some cell phones you can unlock oem. these cell phones are subsidize by the cell phone company and you can only use the cell phone on their network. that is the reason you cannot unlock it from business perspective. you subscribe 5 year phone plan and cell phone is free promotions. What you have wrong tech advice telling people you can unlock it when you cannot.

tech2025 -

Motorola g41

Jose -

Hello,

I am getting the following error; Any idea why could I do?

$ fastboot flashing unlock or $ fastboot oem unlock

FAILED (remote: 'unknown command')
fastboot: error: Command failed

cvaa -

The LG G5 works a bit differently, LineageOS has great instructions for that device, though.

Sebastian -

Forgot to mention it is LG G5 phone.

cvaa -

Hello , Why am i getting this error,?

C:\Program Files (x86)\adb_fastboot>fastboot oem unlock

...

FAILED (remote: Token Verify Failed, Reboot the device

)

finished. total time: 0.004s

C:\Program Files (x86)\adb_fastboot>fastboot oem unlock 445G-H3CN-YRUR-UOX

...

FAILED (remote: Token Verify Failed, Reboot the device

)

finished. total time: 0.005s

I used fastboot flashing unlock also but nothing, same error.

Note- The phone I am trying to unlock was locked using ADB ( fastboot oem lock ).

Please help. I used even Xiaomi's official unlock tool (latest v) but says " This device is not activated. Please activate it and try again.

Thank You!

Hacker Aro -

ich bekomme nachdem "fastboot flashing unlock" die Meldung "wait for any device". Was habe ich falsch gemacht?

rene -

Das bedeutet das er kein verbundenes Gerät erkennt. Das könnte viele Gründe haben, z. B. ein Wackelkontakt im Stecker, ein billiges Kabel oder ein USB 3 Kabel. Fastboot ist aus irgendeinem Grund im Gegensatz zu ADB recht empfindlich.

Sebastian -

Was gibt es für Möglichkeiten den bootloader anderweitig zu entriegeln? ich habe jetzt schon viele Kabeln an unterschiedlichen buchsen verbunden, unterschiedliche treiber und adb tools versucht. ich verzweifle allmählich.

rene -

Was für ein Handy hast du denn? Es könnte auch sein, dass der Bootloader auf deinem Handy nicht entsperrt werden kann.

Sebastian -