Bootloader unlocking: Difference between revisions

The bootloader is the core layer of a computerized device that connects the software to the physical hardware. In smartphones, the bootloader allows the mobile device to start up with an operating system such as iOS for [[iPhone|iPhones]] and [[Android]] for most other smartphones. Bootloaders are typically established by the manufacturer and shipped to retailers and consumers in a "locked" state, thereby tying the hardware to a specific operating system chosen by the manufacturer. To [[wikipedia:Bootloader_unlocking|unlock a bootloader]] is to disconnect the physical device from a particular operating system, allowing users more control over their purchased smartphones. This is especially relevant for users who wish to de-Google their Android devices, which involves removing Google products and services for privacy, flexibility, and other concerns.  

Unlocking the bootloader of a smartphone enables the user to install an alternative operating system on the device, also more commonly known as a custom ROM.<ref>{{Cite web |date=19 Aug 2025 |title=Android ROM |url=https://www.pcmag.com/encyclopedia/term/android-rom |url-status=live |archive-url=https://web.archive.org/web/20241223222958/https://www.pcmag.com/encyclopedia/term/android-rom |archive-date=23 Dec 2024 |website=PCMag}}</ref>

Rooting grants runtime privileges, that is, while the OS is running.

BL unlock allows rewriting the storage drive where the OS is installed, but only while the OS is not running.

BL unlock enables the user to get root access, either:

*Manually, if the user knows what to do

==='''1. Better Privacy'''===

On a default Android system, there is a deep integration with [[wikipedia:Google_Play_Services|Google Play Services]] (and [[Google Mobile Services]] (GMS)). This is a system process that requires access to files, contacts, storage, call logs, SMS messages, location, camera, and microphone. And without this process running, basic system apps will not function.<ref>{{Cite web |last=Aragon |first=Jonah |date=21 Jul 2024 |title=Android |url=https://www.privacyguides.org/en/android/#install-a-custom-distribution |url-status=live |access-date=17 Aug 2025 |website=Privacy Guides |archive-url=http://web.archive.org/web/20260131014956/https://www.privacyguides.org/en/android/ |archive-date=31 Jan 2026}}</ref> Alternative systems avoid this process entirely, or use a privacy-preserving workaround such as:

==='''2. Expanding Device Lifespan'''===

Most custom ROMs are free of [[bloatware]] and can thus be used to extend the longevity of phones that have become unusable due to the default system growing larger with each manufacturer update. Especially on low-end phones, these updates often exhaust the built-in storage after as little as two years. This renders the devices slow and unstable, leaving no room for user data. Custom ROMs are typically much smaller than the manufacturer's software. Consequently, many old phones can run even faster with a custom ROM than they did when new, thus often more than doubling their useful lifespan.<ref>{{Cite web |title=By how much do custom roms really extend Phone lifespans? |url=https://www.reddit.com/r/AndroidQuestions/comments/gdq2rc/comment/fpj11ay/ |access-date=2025-08-23 |website=Reddit |archive-url=https://web.archive.org/web/20260223033349/https://old.reddit.com/r/AndroidQuestions/comments/gdq2rc/by_how_much_do_custom_roms_really_extend_phone/fpj11ay/ |archive-date=23 Feb 2026}}</ref><ref>{{Cite web |date=2023-03-10 |title=Xiaomi Redmi 8a - olivelite with Dual Sim |url=https://community.e.foundation/t/xiaomi-redmi-8a-olivelite-with-dual-sim/29192/12 |url-status=live |access-date=2025-08-23 |website=/e/OS Community |archive-url=http://web.archive.org/web/20250907145946/https://community.e.foundation/t/xiaomi-redmi-8a-olivelite-with-dual-sim/29192/12 |archive-date=7 Sep 2025}}</ref><!-- Please provide better sources than forums and reddits. You can read the citation guide on this wiki for more tips -->

==='''3. Updates after the manufacturer abandons the device'''===

Low-end devices usually receive only a few years or even months of security updates.<ref>{{Cite web |title=Android Update Matrix |url=https://www.androidupdatetracker.com/update-matrix |access-date=2025-08-23 |website=Android Update Tracker |url-status=live |archive-url=http://web.archive.org/web/20251206020040/https://www.androidupdatetracker.com/update-matrix |archive-date=6 Dec 2025}}</ref> Since most custom ROMs are built by the open-source community, installing one of these custom ROMs allows users to receive security updates for the Android system and default components, such as web browser engines and PDF readers, for a significantly longer period than with the manufacturer's OS.<!-- Source? -->

 

==='''4. Customization'''===

Some applications cannot be removed easily with the default OS. A custom ROM can be used only to include the applications the user wants, potentially with customization options that aren't initially available by default. <ref>https://www.reddit.com/r/privacy/comments/k2320l/cant_delete_certain_apps_on_android_only_disable/ ([http://web.archive.org/web/20230615024140/https://old.reddit.com/r/privacy/comments/k2320l/cant_delete_certain_apps_on_android_only_disable/ Archived])</ref>

==Why most devices are locked==

A locked bootloader protects the device from what is often called an [[wikipedia:Evil_maid_attack|Evil Maid Attack]]. This attack occurs when a person with physical access to a device can manipulate the operating system, typically when the device is left unattended or when handed over for inspection by authorities, such as customs, upon entering a country.  

 

A locked bootloader ensures that the operating system remains intact and cannot be altered to deviate from the state in which the manufacturer released it.

Some devices hold [[Digital_rights_management|DRM]] keys, which are deleted when the bootloader is unlocked. Other devices go so far as to wipe proprietary drivers.<ref>{{Cite web |title=Sony wipes TA/ partition |url=https://github.com/melontini/bootloader-unlock-wall-of-shame/blob/4ca762b08e77034db2a5ceb78703ac4789349ed0/brands/sony/README.md?plain=1#L23 |url-status=live |website=GitHub |archive-url=https://web.archive.org/web/20260223033412/https://github.com/zenfyrdev/bootloader-unlock-wall-of-shame/blob/4ca762b08e77034db2a5ceb78703ac4789349ed0/brands/sony/README.md?plain=1 |archive-date=23 Feb 2026}}</ref>

Some mobile carriers have completely restricted the unlocking of bootloaders on specific models of cellphones that they sell.

Unlocking the bootloader is only [[Phones that do not allow bootloader unlock|possible on some, but not all Android devices]].