A bootloader is a small program that runs when a device is turned on. It is responsible for loading the operating system into memory and starting it up. Bootloaders can be used to install new operating systems, troubleshoot problems, and recover from boot failures.
There are many different ways to check the bootloader on a device. The most common method is to use a command-line tool. On Windows, you can use the `bcdedit` command. On macOS, you can use the `bless` command. On Linux, you can use the `grub` command.