First off, the bootloader isn't part of Android, it's what lets the device boot into Android. Device manufacturers generally want you to stick to the version of Android they preloaded on the device.

Developer Ian Morrison has released a new tool called the Linuxium Bootloader which makes it even easier to boot Linux (or Android) on one of these devices. Linuxium Bootloader is a GRUB-like tool ...

In a bid to increase the security of the Android operating system ... pose a problem as Google says that any device with a locked bootloader will use this to check for modifications.

Unlocking smartphone bootloaders isn’t as popular as it used to be, but it’s still an option for those who like to tinker with their technology. You can still unlock the Google Pixel 3 ...

Sony Ericsson recently added a new section to their developer world portal called Unlocking the boot loader. They provide all the information and tools needed to root some of their newer Android ...

Ensuring the integrity of bootloaders is critical to Google's Verified Boot and ... with root privileges on the Android OS to execute arbitrary code as part of the bootloader.

As for the idea of rollback protection, Google will sometimes update a device's bootloader to prevent ... it so that those phones would not boot if an Android 12 build were to be later installed ...

Google's own devices, such as the Nexus One and Nexus S, are among the small minority of Android smartphones that laudably give users a convenient way to unlock the bootloader and install a custom ...