Change Boot Order in BIOS or UEFI to Install Linux
Learn how to boot a Linux installer from USB or DVD by using a one-time boot menu or changing BIOS and UEFI boot priority.
To install Linux from a USB drive or DVD, the computer must start from that installation media instead of immediately starting the operating system on its internal disk. You do this through the computer's firmware, using either a temporary boot menu or a saved boot-order change.
What the Boot Order Does
Firmware is the low-level software that starts the computer before Windows, Linux, or another operating system loads. It checks boot devices in a configured sequence. A boot device is hardware containing software that can start the computer, such as a USB drive, optical disc, SSD, HDD, or network source.
Boot order, also called boot priority, is the saved priority list firmware uses at startup. If the internal disk is first, the computer normally starts the installed operating system before checking a USB drive. To start a Linux installer, the installation media must be selected before the internal disk is attempted.
There are two ways to do this:
- One-time boot menu: Select the installer for the current startup only. This is usually the preferred method when installing Linux once.
- Persistent boot order: Change the saved priority so the USB drive or optical drive is checked first until you change it again.
BIOS and UEFI
BIOS is legacy motherboard firmware that initializes hardware and begins the startup process. UEFI is the modern firmware interface used by most current computers. UEFI provides features such as EFI boot entries, Secure Boot, and a graphical setup utility on some systems.
Manufacturers use different layouts and names. Look for sections or options named Boot, Boot Priority, Boot Sequence, Boot Option Priorities, Startup, or Boot Override. The exact labels and controls depend on the computer or motherboard.
Prepare Before Restarting
- Create the Linux USB drive or bootable CD/DVD correctly before restarting. A normal file copy is not always enough; the image must be written as bootable installation media.
- Connect the USB drive or insert the disc before powering on. A USB device connected after startup may not appear in the boot menu.
- Connect the USB drive directly to the computer when possible. An unreliable hub can prevent the firmware from detecting it.
- On older hardware, try another port, including a USB 2.0 port if one is available.
- Back up important personal data before installing an operating system. Installation choices can overwrite partitions or existing files.
- Optical drives are unavailable on many current laptops and desktops. Use a USB installer if the computer has no CD/DVD drive.
Choose the One-Time Boot Menu
The one-time boot menu is normally the least disruptive method. It selects a device for the current startup without changing the saved boot order. In UEFI firmware, the same feature may be called Boot Override.
- Shut down the computer completely.
- Insert the prepared Linux USB drive or DVD.
- Power on the computer and immediately press or repeatedly tap the boot-menu key.
- Use the arrow keys or on-screen controls to select the USB drive, optical drive, or appropriate EFI boot entry.
- Press Enter and verify that the Linux installer menu or live environment starts.
Common one-time boot-menu keys include F12, F11, and Esc. Some manufacturers use another key. The startup screen may briefly display the correct key, and the device manufacturer's documentation is authoritative.
| Manufacturer or device family | Firmware setup key | One-time boot-menu key | Notes |
|---|---|---|---|
| Many PCs and laptops | F2 or Delete | F12, F11, or Esc | Keys vary by model; read the startup prompt. |
| Some business desktops and laptops | F2, F10, or Delete | F9, F12, or Esc | Vendor-specific startup menus are common. |
| Custom-built desktops | Delete or F2 | F8, F11, or F12 | Motherboard documentation normally lists the keys. |
This table gives representative keys, not a universal key map. Press the key immediately after power-on; waiting until the operating system logo appears may be too late.
Temporary Boot Menu Versus Persistent Boot Order
| Method | How long it applies | Best use case | Risk of disrupting normal startup |
|---|---|---|---|
| One-time boot menu | Current boot only | Try an installer or troubleshoot a boot device | Low; the saved order normally remains unchanged |
| Boot Override | Current boot only | Select a UEFI device from firmware setup | Low; it normally does not edit boot priority |
| Persistent boot order | Until changed again | Repeatedly boot from installation media or a selected device | Medium; leaving removable media first can affect later startups |
Change the Persistent Boot Priority
Use this method if the one-time boot menu is unavailable or if you need a lasting change.
- Power off the computer and connect the USB installer or insert the bootable disc.
- Power it on and immediately press the firmware setup key, commonly F2, Delete, F10, or Esc.
- Open the Boot, Startup, or similarly named section.
- Find the boot-priority list or Boot Option Priorities.
- Move the desired USB drive or optical drive above the internal SSD, HDD, or existing operating-system entry.
- Leave the internal disk available as a later boot option.
- Use the displayed controls to reorder the list. Common controls include arrow keys, Enter, plus and minus, F5 and F6, drag-and-drop, or buttons shown on screen.
- Choose Save and Exit. F10 is a common shortcut, but read the confirmation before accepting it.
A physical device name, such as a USB manufacturer's name, is different from a boot entry such as Windows Boot Manager or a Linux boot manager entry. On a UEFI system, the firmware may list both the physical disk and named operating-system entries.
Select the Correct USB Entry
A single USB drive can appear more than once. For a normal modern Linux installation on a UEFI-capable computer, prefer an entry labeled UEFI or EFI, such as UEFI: USB Drive Name.
| Entry as shown in firmware | Meaning | When to select it |
|---|---|---|
| UEFI: USB Drive Name | Starts the USB in UEFI mode | Preferred for a standard modern UEFI Linux installation |
| EFI USB Drive | Another label for a UEFI USB boot entry | Use when installing Linux in UEFI mode |
| Legacy USB or BIOS USB | Starts the USB using traditional BIOS-compatible mode | Use only for a legacy installation plan or hardware that requires it |
| USB Storage Device | Generic removable-device entry | Use when no separate UEFI or legacy entry is provided |
| CD/DVD or Optical Drive | Boots a disc in the optical drive | Use for a bootable Linux DVD |
| Windows Boot Manager | UEFI startup entry for Windows | Normally keep as a later option while starting installation media |
| Linux boot-manager entry | UEFI entry that starts an installed Linux boot manager | Use after installation for normal Linux startup or dual boot |
| Internal SSD or HDD | Physical internal storage device | Keep available as a later boot option |
Be consistent. If the installer starts in UEFI mode, install the system in UEFI mode. Legacy, BIOS, and CSM entries use legacy compatibility behavior. Mixing modes can produce a system that installs successfully but does not appear in the expected boot entries.
Save, Exit, and Verify
Do not simply leave firmware setup without saving. Select Save and Exit, use the displayed save shortcut, or confirm the equivalent option. After restarting, a successful selection should lead to the Linux installer menu or a live Linux environment.
If installation finishes and the computer starts the installer again, remove the USB drive or DVD when prompted, or shut down and remove it afterward. If the removable media remains first in the saved order, restore the internal disk or the appropriate installed-system boot-manager entry as the first option.
Secure Boot, Legacy Boot, and CSM
Secure Boot is a UEFI security mechanism that validates approved boot software. Many mainstream Linux distributions support Secure Boot, so disabling it is not universally required.
If a particular installer does not start, check the distribution's requirements and the firmware's Secure Boot setting. Change it only when necessary and record the original value so it can be restored.
Legacy Boot is a traditional BIOS-style startup mode. CSM, or Compatibility Support Module, is a UEFI feature that can provide compatibility with legacy booting. Treat Legacy Boot and CSM as troubleshooting options for hardware or installation media that cannot boot in UEFI mode, not as the default choice for a modern installation.
Practical Examples
Modern UEFI laptop with a Linux USB
- Insert the prepared Linux USB drive.
- Power on and open the one-time boot menu, commonly with F12, F11, or Esc.
- Select the entry labeled UEFI or EFI followed by the USB drive's name.
- Confirm that the Linux installer or live environment begins.
- Leave the saved internal-disk boot order unchanged if you only needed this one startup.
Older BIOS desktop with a Linux DVD
- Insert the bootable Linux disc.
- Enter firmware setup using the machine's setup key, such as F2, Delete, or F10.
- Open the Boot section and move the optical drive to the first position.
- Save the change and restart.
Restore normal startup after installation
- Remove the installer USB or DVD.
- If necessary, open firmware setup and place the internal disk or installed Linux boot-manager entry first.
- Save and restart.
- On a dual-boot system, firmware starts the selected disk and a Linux boot manager may then display a menu for Linux and another operating system.
The Linux boot manager's operating-system choices are separate from the firmware's device order. Firmware chooses which device or EFI entry starts first; a boot manager can then choose an operating system on that device.
Troubleshooting
The existing operating system starts instead of the installer
- Open the one-time boot menu and select the installer explicitly.
- For a persistent change, move the USB or optical drive above the internal disk.
- Confirm that the media was created as bootable and that it was connected before startup.
- Try the UEFI version of the USB entry on a modern system.
The USB drive does not appear
- Reconnect it directly rather than through a hub and restart.
- Try another USB port, including a USB 2.0 port on older hardware.
- Recreate the bootable drive and verify the Linux image used to create it.
- Check whether firmware USB boot is disabled or whether the hardware has compatibility limitations.
Two USB choices appear
If one choice is marked UEFI and another is marked Legacy or BIOS, choose UEFI for a modern UEFI installation. Use Legacy or CSM only when required by the hardware, media, or an existing legacy installation plan.
The installer returns to the boot menu
- Verify or recreate the installation media; it may be damaged or improperly written.
- Try the boot entry matching the intended installation mode.
- Review Secure Boot and Legacy/CSM settings carefully rather than changing several unrelated settings at once.
Firmware setup will not open
- Use the startup-screen prompt and the manufacturer's instructions to identify the correct key.
- Restart and repeatedly tap the expected key immediately after power-on.
- Fast startup can shorten the time available. If the existing operating system provides an advanced restart option for UEFI firmware, use that path when available.
The installer starts repeatedly after Linux is installed
- Remove the USB drive or DVD.
- Restore the internal disk or the correct Linux boot-manager entry as the first permanent boot option.
- Save the firmware change and restart.
Key Points to Remember
- Use the one-time boot menu when you only need to start installation media once.
- Use persistent boot priority when a lasting change is necessary, and save before exiting.
- On modern systems, select the UEFI or EFI USB entry for a normal UEFI installation.
- Keep the internal disk available as a later boot option.
- Secure Boot often works with mainstream Linux; disable it only when the specific media requires that change.
- After installation, remove the media and restore normal internal-disk or boot-manager priority if needed.
For broader Linux topics, see Linux. This procedure normally happens before the operating system starts, so Linux terminal commands are usually not required.