Bootloader unlocking
Bootloader unlocking is the process of disabling the bootloader security that enforces secure boot during the boot procedure. It can allow advanced customizations, such as installing custom firmware. On smartphones, this can be a custom Android distribution or another mobile operating system.
Some bootloaders are not locked at all and some are locked, but can be unlocked with a command, a setting or with assistance from the manufacturer. Some do not include an unlocking method and can only be unlocked through a software exploit.
Bootloader unlocking is also done for mobile forensics purposes, to extract digital evidence from mobile devices, using tools such as Cellebrite UFED.
Background
Unlocking the bootloader allows installing and running unsigned code on a device, including user customized software. Operating outside the manufacturer specification might usually result in voiding any warranties and may make the device susceptible to data theft, as the integrity of the operating system can no longer be guaranteed. On Chromebooks, enabling developer mode makes the system less secure than a standard laptop running Linux. Unlocking the bootloader may require reinitialization, formatting to factory settings, or otherwise lead to data loss on Android and ChromeOS devices. This is due to the fact that some user data is impossible to back up without root permission. This will also lead to certain security apps not working, such as Samsung Knox for which the counter would be stuck at "0x1."Sascha Segan from PCMag considered a locked bootloader a mistake on the Qualcomm Snapdragon Insiders phone, which is targeted at advanced users.
Platforms
Android">Android 16">Android
Unlocking the bootloader is typically a prerequisite of obtaining root access and/or installing a custom ROM.| Manufacturer | Difficulty level | Method |
| Easy Medium | Command-line | |
| Samsung | Complicated
| Enable option that allows OEM unlock in Development settings, then unlock bootloader in Download mode. Samsung Knox will be permanently tripped if modified or custom firmware is flashed, so Samsung Wallet, Secure Folder and applications made use of the Knox framework will be permanently unusable even if the bootloader is re-locked. Prior to One UI 8.0, Devices sold outside of North America had the OEM Unlock option to unlock the bootloader. From One UI 8.0, Samsung has removed the ability to unlock the bootloader in all regions. |
| OnePlus | Easy Medium | Command-line, except on T-Mobile US variants where an unlock code is needed |
| Xiaomi | Hard Very Hard Impossible | Requires a 3-7 day old Mi account. On devices with Xiaomi HyperOS outside mainland China, you need to request bootloader unlock permissions in the Xiaomi Community app before proceeding with bootloader unlocking. Requires a 1-month-old Xiaomi account. For Mainland China devices with HyperOS, bootloader unlock has not been available since February 2025. |
| Asus | Impossible | Unavailable since August 2023, when first-party apps were removed and servers were shut down. |
| Sony | Medium | Command-line, request code at Sony website |
| Fairphone | Medium | Command-line, request code at Fairphone website or forum |
| Motorola | Varies widely between model and SoC manufacturer Medium Impossible | Command-line, request code at Motorola website |
| Realme | Medium-Hard Impossible | Command-line, after installation of the in-depth test app and submitting an application for in-depth testing. |
| Nothing | Easy | Command-line |
| Huawei | Medium-Hard Impossible | Select Huawei phones using the Kirin SoC can have their bootloader unlocked unofficially via potatonv: https://www.xda-developers.com/huawei-honor-bootloader-unlock-potatonv/ For other devices, bootloader unlock has not been available since July 2018. |
| OPPO | Easy or phones that bought in mainland China Medium. | Only certain Snapdragon-powered OPPO phones can be unlocked without a third-party paid tool such as UnlockTool. Unlocking is possible on some MediaTek SoCs via MTKClient. Note that certain fastboot binaries have been removed, or locked by RSA key. MediaTek: MTKClient can be used for older devices, which sometimes requires using MTK bypass utility beforehand. This is unfeasible on modern Mediatek SoCs as they require a download agent file signed by the OEM and this file is not typically distributed. Any phones bought from mainland China and in depth-test's device support lists: Depth test regardless of SoC. Command line using adb and fastboot. |
| HMD-Nokia | Medium Impossible | Possible with unofficial unlocking methods |
| Vivo | Impossible as of May 2022. | N/A |
| LG | Hard | Possible by flashing bootloaders with QFIL utility. |
| Tecno | Medium | Command-line. Requires Tecno ID account at least two weeks old. |
| Infinix | Medium | Command-line. Requires Inifinix ID account at least two weeks old. |
| Itel | Medium | Command-line. Requires Itel ID account at least two weeks old. |
| TCL | Medium Unknown | For the Ion V mobile phone, you can use a Python tool to reboot to a normally hidden fastboot. |
| Amazon | Medium | Command-line and unofficial. Requires using Linux to brick the device temporarily. |
History
The bootloaders of Nexus and Pixel devices can be unlocked with fastboot.When Motorola released a bootloader unlocking tool for the Droid Razr, Verizon removed the tool from their models.
In 2011, Sony Ericsson released an online bootloader unlocking tool. Sony requires the IMEI number to be filled in on their website. For the Asus Transformer Prime TF201, Asus has released a special bootloader unlock tool.
In 2012, Motorola released a limited tool for unlocking bootloaders. They require accepting terms and conditions and creating an account before the bootloader can be unlocked for your Motorola device.
A 2012 article by The Verge called the unlockable bootloaders a 'broken promise' and called for a fix.
HTC phones have an additional layer of lock called "S-OFF/S-ON".
Bootloaders can be unlocked using an exploit or using a way that the vendor supplied. The latter method usually requires wiping all data on the device. In addition, some manufacturers prohibit unlocking on carrier locked phones. Although Samsung phones and cellular tablets sold in the US and Canada do not allow bootloader unlocks regardless of carrier status, a service has allowed users on an earlier version to unlock their US/Canadian Samsung phone and/or tablet
In 2018, a developer from XDA Developers launched a service which allowed users to unlock the bootloader of some Nokia smartphone models. Similarly, another developer from XDA Developers launched a service to allow users to unlock the bootloaders of Samsung Galaxy S20 and Samsung Galaxy S21 Phones.
Huawei announced plans to allow users to unlock the bootloader of the Mate 30 series, but later retracted that. Huawei has stopped providing bootloader unlock codes since 2018. A bootloader exploit named checkm30 has been developed for HiSilicon based Huawei phones.
When the bootloader of the Samsung Galaxy Z Fold 3 was unlocked, the camera became less functional. This could be restored by re-locking the bootloader. This issue was later fixed by Samsung. For the Samsung Galaxy S22 series, unlocking the bootloader has no effect on the camera.
Others
Microsoft
The WPInternals tool is able to unlock bootloaders of all Nokia Lumia phones running Windows Phone, but not phones like the Alcatel Idol 4 or HP Elite x3. Version 1.0 was released in November 2015. In October 2018, the tool was released as open source software when the main developer René Lergner stepped down.The slab bootloader used by Windows RT could be unlocked using a vulnerability, but was silently patched by Microsoft in 2016. UEFI Secure Boot on x86 systems can generally be unlocked.
Apple
The boot ROM protection on iOS devices with an A11 processor or older can be bypassed with a hardware exploit known as checkm8, which makes it possible to run other operating systems including Linux.The bootloader on Apple Silicon-based Macs can be unlocked. However, other Apple devices like the iPhone and iPad cannot be bootloader unlocked even when using the same chip used in a Mac.
In 2013, the bootloader of the Chromecast was hacked using an exploit. In 2021, it was hacked again for newer versions. In 2023, it was reported that the Chromecast HD could be unlocked without exploit.
Asus
used to provide an Unlocking tool for both of their smartphone lines, the Zenfone and ROG Phone. This worked as an installable.apk file that the user could install on their phone, then unlock the bootloader. The app worked by contacting Asus unlocking servers, then prompting the user to perform a factory reset.In 2023 Asus removed the tool from their website and closed the unlocking servers, so even phones with the.apk file installed couldn't unlock their bootloaders. Representatives on the Asus forums claimed the tool would be available again, but as of March 2024 no additional information has been provided, even after the release of their latest device the ROG Phone 8 and the upcoming release of the Zenfone 11 Ultra.
A user on the popular forum XDA filed a court claim application against Asus due to the unlock tool never being released and alleged that Asus censored comments about the unlock tool on their forum.