How to enter the UEFI / BIOS

Overview

This guide explains how to access your system’s firmware settings (UEFI or legacy BIOS) in order to change hardware-level options.

NOTE

UEFI vs Legacy BIOS: UEFI is the modern firmware standard and allows direct access from within Windows. Legacy BIOS is older firmware with no OS-level entry point — the only way in is through keyboard input at boot time (POST).

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Check if your System is UEFI or BIOS

Before trying any method, confirm your firmware type.

If you are on Windows

Open PowerShell and run:

bcdedit /enum

Look for the path field:

Output	Firmware type
\Windows\system32\winload.efi	✅ UEFI
\Windows\system32\winload.exe	❌ Legacy BIOS

If you are on Linux

The kernel exposes firmware info directly via the filesystem. Run:

[ -d /sys/firmware/efi ] && echo "UEFI" || echo "Legacy BIOS"

If the system booted in UEFI mode, the kernel mounts the EFI variables filesystem at /sys/firmware/efi. If that directory does not exist, the system booted in legacy BIOS mode.

You can also inspect it manually:

ls /sys/firmware/efi

Result	Firmware type
Directory exists and lists files (e.g. efivars, vars)	✅ UEFI
No such file or directory	❌ Legacy BIOS

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UEFI: Enter from Windows

Warning

These methods only work if your system is booted in UEFI mode.

Via CMD command

Open PowerShell as Administrator:

shutdown /r /fw /t 0

Windows passes the /fw flag to the UEFI boot manager, which redirects directly to the firmware setup on next boot. This is the cleanest and most reliable method.

Advanced Startup (GUI)

Navigate to:

Settings → System → Recovery → Advanced startup → Restart now

Or use the shortcut: hold Shift and click Restart.

Once in the recovery environment, follow this path:

Troubleshoot → Advanced options → UEFI Firmware Settings → Restart

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Legacy BIOS: Enter at Boot

NOTE

The following methods can also work in UEFI firmwares

There is no OS-level method to enter a legacy BIOS. Windows has no communication channel with legacy firmware. The only option is keyboard input during POST.

Key press at POST

1. Restart the system normally from Windows
2. As soon as the screen turns on (during POST), repeatedly press the firmware key for your manufacturer:

Manufacturer	Common key(s)
Dell	F2, F12
HP	F10, Esc
Lenovo	F1, F2, Enter then F1
Asus	DEL, F2
Acer	F2, DEL
MSI	DEL
Generic / unknown	DEL, F2, F10

Slow down POST

If the system boots too quickly to catch the key press:

• Disable Fast Boot from Windows power settings
• Disconnect secondary storage drives to slow down POST enumeration

These are workarounds, not direct entry methods.

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⚠️ Last Resort: CMOS Reset

If you cannot access the firmware in any way:

• Jumper method: locate the CMOS reset jumper on the motherboard and short it for a few seconds with the system powered off
• Battery method: remove the CMOS coin cell battery (CR2032) for ~30 seconds, then reinsert it

WARNING

Both methods reset all BIOS/UEFI settings to factory defaults, including boot order, SATA mode, and any custom configuration!