How to Disable Fast (Quick) Boot When BIOS and UEFI Are Inaccessible

1. Introduction

Basic Input Output System (BIOS) and Unified Extensible Firmware Interface (UEFI) are the two major (machine) motherboard firmware options. Since they are responsible for the system core hardware and software settings in addition to the machine and operating system (OS) boot process, being able to enter and work with either system is paramount. Yet, in some situations, an administrator might be hindered in this aspect.

In this tutorial, we talk about a common boot option that may prevent entry to the BIOS or UEFI setup for a given machine. First, we go over the basic functions of machine firmware and ways to access its settings. After that, we discuss a specific option that enables faster booting in some cases but might hinder access to BIOS and UEFI. Finally, we go over workarounds in these cases.

We tested the code in this tutorial on Debian 12 (Bookworm) with GNU Bash 5.2.15. Unless otherwise specified, it should work in most POSIX-compliant environments.

2. BIOS and UEFI

Although there are multiple fundamental differences between them, both BIOS and UEFI control various core aspects of the machine in which they exist. Generally, BIOS is the older firmware and UEFI is its replacement. Still, they often coexist for compatibility and historical reasons.

2.1. General Features

To begin with, let’s see some of the main features of BIOS:

• POST (Power-On Self-Test) and OS bootstrapping
• boot order configuration
• system voltage setup
• set internal date and time
• processor, RAM, and storage configuration
• keyboard, mouse, and other peripheral setup
• toggle and tweak various hardware
• security setup

UEFI enhances these by often providing a better graphical interface, quicker booting, drastically improved security, storage structure, and hardware support.

Notably, some features are only available for specific operating systems.

2.2. Entering the Firmware Setup

In the simplest case of a brand new machine, we usually either go into the BIOS or UEFI settings directly at boot, since there’s no OS to load. Alternatively, a primary peripheral such as a keyboard is required to press a specific key (Return, Escape, F2, F8, F10).

However, an OS-specific feature might prevent this behavior.

3. Firmware Fast Boot (Quick Boot, Fast Start, Fast Startup)

After installing Microsoft Windows, one might be able to activate a specific feature that targets this OS in the BIOS or UEFI settings. Its name can differ:

• Fast Boot
• Quick Boot
• Fast Start
• Fast Startup

In all cases, it comes down to a way to load the Windows OS faster after powering off the machine. Effectively, the feature stores all open files and processes during shutdown and restores them upon starting. Thus, the OS loads faster instead of booting from scratch each time.

However, this means that the regular boot process is drastically shortened and reduced to the point of potentially not being able to enter BIOS or UEFI. Let’s see what we can do to work around this.

4. Disable Fast Boot

Even when Fast Boot is already on, which makes BIOS and UEFI settings hard to access using conventional means, there are often ways to attempt and enter the firmware setup, so we can disable the feature.

4.1. OS System Firmware Force-Boot

In both Linux distributions Microsoft Windows, there are commands to reboot into the firmware setup.

In the case of Linux, we can use systemctl with the reboot subcommand and the –firmware-setup option:

$ systemctl reboot --firmware-setup

This way, the machine should force-boot into BIOS or UEFI

However, this may not be a viable option in all cases, as the communication from the OS to BIOS or UEFI depends on the implementation on both sides. So, let’s look into alternatives.

4.2. Bootloader (GRUB)

Of course, a bootloader dictates how the system loads and might be able to revert to the firmware in some cases.

Specifically, if it exists, we can use the UEFI Firmware Settings entry in the GRUB menu and set it as the default option.

In some instances, we might even be able to create this option, although not having it with a fully working UEFI (OS) usually means that communication from the operating system to the firmware is limited.

4.3. Hardware Reset

Since the system firmware runs on hardware, knowing how to directly manipulate the latter to reset the former is a way to circumvent restrictions. All motherboards should include instructions for restoring their factory defaults.

In the most common case, this involves several steps but leads to losing all custom settings since the motherboard was first used:

1. open machine case
2. locate motherboard
3. find a specific (often button-shaped) battery
4. extract the battery
5. short specific motherboard pins
6. reinsert the battery

This should disable any non-essential features, allowing the machine to boot. However, since we usually need to handle hardware internals directly and the system loses all custom configurations, a hardware reset is most often a method of last resort.

5. Summary

In this article, we talked about a firmware option that enables faster booting for some operating systems but might prevent us from getting into the BIOS or UEFI setup.

In conclusion, although often harder, there are alternative means to gain access to the firmware options of a machine even when conventional methods are not immediately available due to features like Fast Boot.