BIOS and firmware are the software that runs before your operating system starts

BIOS (Basic Input/Output System) is the first program your computer runs when you press the power button. It checks that your hardware is working, finds your hard drive or SSD, and hands control to Windows, macOS, or Linux. Firmware is the same kind of low-level software that runs on other devices — your router, printer, phone, or motherboard — to make them work at all.

On newer computers, BIOS has been replaced by UEFI (Unified Extensible Firmware Interface), which does the same job but with a better interface and more features. Most people still call it BIOS out of habit, and manufacturers often use the terms interchangeably. The distinction matters less than understanding that this is the layer between your hardware and your operating system — it is not something you interact with in Windows or macOS, but it is always running underneath.

You do not need to update BIOS or firmware unless something is broken, a security problem has been found, or you are adding new hardware that the current version does not recognize. Most computers work fine for years without a BIOS update. When an update is necessary, the manufacturer will tell you why, and you should read that reason before proceeding.

Key Takeaways

  • BIOS and firmware are the software layer between your hardware and your operating system, and they run before Windows or macOS starts.
  • You only need to update BIOS or firmware if the manufacturer identifies a problem, a security issue, or a hardware compatibility issue that affects you.
  • BIOS updates carry real risk — a power loss or interruption during the update can make your computer unbootable — so do not update on a whim or a laptop running on battery.
  • The process differs by manufacturer, so you must follow the exact steps for your specific computer model, not generic instructions.
  • Firmware updates for other devices (routers, printers, phones) follow the same principle: only update when the manufacturer recommends it for a specific reason.

When a BIOS or firmware update is actually necessary

The most common reasons to update are security patches, hardware compatibility, and bug fixes. If a security researcher discovers a flaw that could let someone access your computer before Windows loads, the manufacturer releases a BIOS update to close it. If you buy a new CPU or add a new type of storage drive, the BIOS might not recognize it until you update. If your computer is freezing, not waking from sleep, or not detecting all your RAM, a BIOS update might fix it.

You will know an update is necessary because the manufacturer will announce it on their support page for your specific model, usually with a list of what it fixes. Check your computer's model number (often on a sticker on the bottom or back), go to the manufacturer's website, and search for BIOS updates for that model. If there is nothing listed, or if the listed updates are for problems you do not have, you do not need to update.

Do not update BIOS because it is available, because a website tells you to, or because you think it might improve performance. BIOS updates are not like Windows updates — they are rare, they carry risk, and they are only meant to fix specific problems. Updating unnecessarily is how people end up with computers that will not start.

The risks of updating BIOS and how to avoid them

A BIOS update is different from a regular software update because it rewrites the firmware on your motherboard. If the power cuts out during the update, if your computer crashes, or if the update is interrupted for any reason, your motherboard can be left in a state where it cannot boot at all. A failed BIOS update is not something you can fix by restarting — you may need to send the computer to a repair shop or replace the motherboard.

To minimize this risk, follow these rules: use a desktop computer or a laptop plugged into power, not a laptop running on battery. Close all other programs. Disable sleep mode and screen lock so nothing interrupts the update. Do not touch the computer during the update — do not move it, do not unplug it, do not press any keys. Read the manufacturer's instructions completely before you start, because the process varies by brand and model.

Some manufacturers offer a safer method: updating BIOS from within Windows using their update tool, rather than from a USB drive at startup. If your manufacturer offers this option, use it — it is less likely to fail. If you must update from a USB drive, use a reliable drive and follow the exact steps in the manual.

How to find and read the correct BIOS update for your computer

Start by identifying your exact computer model. On a Dell, HP, Lenovo, or Asus, this is usually a model number like "XPS 13" or "ThinkPad E15" printed on the bottom or back. On a Mac, click the Apple menu, select "About This Mac", and note the model identifier. On a custom-built PC, you need the motherboard manufacturer and model number — restart the computer, watch the startup screen for a message that says "Press [key] to enter Setup" or "BIOS", and press that key to see the motherboard information.

Once you have the model number, go to the manufacturer's official support website. Search for your model and look for a section called "BIOS", "Firmware", "Downloads", or "Drivers". read the BIOS file to your computer — it will usually be a .exe file (Windows), a .dmg file (Mac), or a .bin file (if you need to put it on a USB drive). Do not read BIOS from any website other than the official manufacturer site, because a corrupted or wrong file will definitely break your computer.

Before you read, check the release notes to confirm this update is for your exact model and that it addresses a problem you actually have. The release notes will say something like "Fixes issue where computer does not recognize 32GB of RAM" or "Security update for CVE-2024-1234". If the update is for a different model or a problem you do not have, do not install it.

The step-by-step process for updating BIOS on Windows computers

The process depends on your manufacturer, but the general flow is the same. First, plug in your computer and make sure the battery is fully charged if it is a laptop. Close all programs, disable sleep mode (go to Settings > System > Power & Sleep and set both timeouts to "Never"), and disable any antivirus software temporarily.

If the manufacturer provides a Windows process to update BIOS, read it, run it, and follow the on-screen instructions. The process will usually restart your computer automatically and handle the update during startup. Do not interrupt this process — let it finish completely, even if it seems to be taking a long time.

If you need to update from a USB drive, format a USB drive to FAT32, copy the BIOS file to the root of the drive, insert it into your computer, restart, and press the key shown on the startup screen to enter the BIOS menu (usually Delete, F2, F10, or F12 — check your manual). Navigate to a menu option like "Update BIOS", "Flash BIOS", or "Firmware Update", select the file on the USB drive, and confirm. The computer will restart automatically when done.

Updating firmware on other devices like routers and printers

Routers, printers, and other networked devices also have firmware that can be updated. The principle is the same: only update if the manufacturer recommends it for a specific reason, and follow their exact instructions. For a router, log into the admin panel (usually by typing 192.168.1.1 in a web browser), look for a "Firmware" or "System" section, and check for updates. For a printer, go to the printer's settings menu or use the manufacturer's software on your computer.

Firmware updates for these devices are generally safer than BIOS updates because they are designed to be interrupted and resumed. Still, do not unplug the device during an update, and do not restart it unless the instructions say to. If an update fails, the device will usually try again the next time you restart it, or you can retry the update manually.

Phone and tablet firmware (called OS updates on these devices) works differently — they are designed to be safe and can usually be interrupted without damage. You can update your phone while on battery, and it is generally safe to do so. The same caution applies, though: only update if you have a reason, and do not update if your battery is below 20 percent.

What to do if a BIOS update fails or your computer will not start

If your computer restarts after a BIOS update and boots normally, the update succeeded. If it restarts but gets stuck on a black screen, shows an error message, or will not boot at all, the update may have failed. Do not panic — try these steps in order.

First, force a restart by holding the power button for 10 seconds, then release it and let the computer start normally. Sometimes a failed update will recover on its own. If that does not work, try restarting again and pressing the key to enter BIOS (usually Delete, F2, F10, or F12). If you can get into BIOS, look for an option to reset to default settings or restore a previous BIOS version. Some computers keep a backup of the old BIOS and can revert automatically.

If you cannot get into BIOS, cannot restart the computer, or the computer will not respond to anything, the BIOS update has likely failed in a way that requires professional repair. Contact the manufacturer's support line with your model number and explain what happened. They may be able to walk you through a recovery process, or they may need to repair the computer. This is rare, but it is why updating BIOS unnecessarily is not worth the risk.

Frequently Asked Questions

How often should I check for BIOS updates?

You do not need to check regularly. Check only if you are experiencing a specific problem, adding new hardware, or if the manufacturer announces a security update that affects your model. You can check once a year if you want peace of mind, but most computers work fine for years without any BIOS update.

Is it safe to update BIOS on a laptop?

Only if the laptop is plugged into power and fully charged. Never update BIOS on a laptop running on battery — a power loss during the update will brick the computer. If you have a laptop, plug it in, let it charge to 100 percent, and keep it plugged in throughout the entire update process.

What does "flashing" BIOS mean?

Flashing is the process of writing new firmware to the chip on your motherboard. It is the same thing as updating BIOS — the terms are used interchangeably. The word "flash" comes from the type of memory chip used to store BIOS, which can be erased and rewritten.

Can I update BIOS if I have an SSD instead of a hard drive?

Yes. BIOS updates work the same way regardless of what storage drive you have. The BIOS itself is stored on your motherboard, not on your hard drive or SSD, so the type of storage does not matter.

What if the BIOS update is for a security problem but I do not use the internet?

If your computer is not connected to a network and you do not plan to connect it, a security update is less urgent. However, if you ever plan to use the internet, connect to a network, or take the computer somewhere else, you should still update — security problems can be exploited even if you do not notice them happening.