BootOrder

BootOrder refers to the sequence of boot devices or boot entries that a computer's firmware (BIOS or UEFI) consults when searching for a bootable operating system or bootloader. The order determines which device is tried first, second, and so on — for example internal disk, optical drive, USB device, or network (PXE).

In legacy BIOS systems the boot sequence is a simple priority list of device types. In UEFI systems BootOrder is typically implemented as a firmware variable that contains an ordered list of Boot#### entries; each Boot#### entry describes a specific boot option and points to a device path or to a boot manager. Operating systems, firmware setup utilities, vendor tools and command-line utilities (for example efibootmgr on Linux) can read and modify this order. Many systems also provide a one-time boot menu to select a device for a single boot without changing the persistent BootOrder.

Practical uses include selecting a media for OS installation or recovery, configuring network boot for diskless clients, or managing multi-boot setups. BootOrder can interact with features such as Secure Boot and Fast Boot, and incorrect ordering can prevent expected devices from being used. Firmware updates, changes in hardware enumeration, or malicious bootkits can alter the BootOrder, so administrators often combine secure firmware settings and access controls to protect boot configuration.