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DRAFT

Update the Intel NUC BIOS

This runbook walks you through updating the BIOS on an Intel NUC (including ASUS-manufactured NUCs) using a USB drive. A current BIOS is recommended before installing Ubuntu or Talos—follow this runbook before Ubuntu Setup or Intel NUC Talos Bootstrapping.

Overview

Updating the Intel NUC BIOS involves:

  1. Downloading the BIOS update — From the manufacturer support page for your NUC model
  2. Extracting the update files — Unzip to get the .bio file and IFLASH2.exe
  3. Setting Windsor context — Initialize the nuc-bios context with windsor init nuc-bios
  4. Updating windsor.yaml — Setting BIOS_FOLDER and USB_DISK in windsor.yaml
  5. Copying files to the devices folder — Using task device:prepare-bios
  6. Writing the BIOS update to USB — Formatting USB as FAT32 and copying files with task device:write-bios-disk
  7. Booting and applying the update — Boot the NUC from the USB drive (F7) and run the update

Prerequisites

  • Intel NUC device — Compatible Intel NUC (x86_64)
  • USB memory device — At least 1GB, will be formatted (all data erased)
  • Computer with macOS or Linux — For preparing the USB
  • Physical access — To the NUC for power and boot media
  • Windsor workspace — Clone or open the workspace repository

Step 1: Download the BIOS Update

Find Your NUC Model

Identify your NUC model (e.g. NUC8i5BEH, NUC8i3BEH). It is usually printed on the device or visible in the current BIOS.

Download from Manufacturer

Visit the manufacturer support page for your NUC model and download the latest BIOS:

Model BIOS Downloads
ASUS NUC8i5BEH ASUS Support
ASUS NUC8i3BEH ASUS Support

For other models, search for "<your-nuc-model> BIOS download" or visit Intel NUC support.

Extract the BIOS Update

  1. Download the BIOS ZIP file (e.g. NUC8i5BEHAS003.BI.zip)
  2. Extract the ZIP to a folder (e.g. ~/Downloads/NUC8i5BEHAS003)
  3. Confirm the folder contains:
  4. A .bio file (e.g. NUC8i5BEH.003.bio)
  5. IFLASH2.exe (ASUS NUC firmware update utility)

Note: The exact filenames depend on your model and BIOS version.

Step 2: Set Windsor context

Initialize and set the nuc-bios context:

windsor init nuc-bios
windsor context set nuc-bios

Step 3: Update windsor.yaml

Determine the target USB disk

Use task device:list-disks to identify your USB device:

task device:list-disks

Note the device identifier (e.g. /dev/disk4). Use the correct disk — writing to the wrong device can destroy data.

Add variables to windsor.yaml

Add or update the environment section in contexts/nuc-bios/windsor.yaml:

environment:
  # Path to the extracted BIOS update folder (contains .bio and IFLASH2.exe)
  BIOS_FOLDER: "/Users/$USER/Downloads/BECFL357"

  # USB device for the BIOS update (use task device:list-disks to identify)
  USB_DISK: "/dev/disk4"

Replace BIOS_FOLDER with the full path to your extracted BIOS folder, and USB_DISK with your USB device.

Step 4: Prepare BIOS Files in the Workspace

Copy the BIOS update files from your downloads folder to the workspace devices directory:

task device:prepare-bios

This copies the contents of BIOS_FOLDER to contexts/nuc-bios/devices/bios/.

Step 5: Write the BIOS Update to USB

This task will erase the USB device, format it as FAT32, and copy the BIOS files:

task device:write-bios-disk

Warning: All data on the USB device will be destroyed. Ensure no important data is on the drive.

Step 6: Eject the USB Device

Safely eject the USB drive:

task device:eject-disk

Step 7: Boot the NUC and Apply the BIOS Update

  1. Insert the USB drive into a USB port on the Intel NUC
  2. Power on the NUC (or restart if it is already on)
  3. Press F7 during boot to open the boot menu (or the key shown on screen for "Boot Menu")
  4. Select the USB device from the boot menu
  5. Reboot when the update finishes

Step 8: Verify the BIOS Version

  1. Reboot the NUC and press F2 to enter BIOS Setup
  2. Check the BIOS version on the main screen
  3. Configure boot settings as needed (e.g. USB boot, Secure Boot) for your next installation

Troubleshooting

USB Device Not Detected During BIOS Update

  • Reformat the USB as FAT32 and ensure Quick Format is deselected
  • Use a different USB drive
  • Try a USB 2.0 port if USB 3.0 fails

Write Task Fails on macOS

  • Ensure the USB disk is not in use (close Finder windows showing the drive)
  • Run diskutil unmountDisk /dev/disk<N> before retrying
  • Verify USB_DISK points to the correct device with task device:list-disks

Update Fails or NUC Does Not Boot

  • Do not interrupt the update; wait for it to complete
  • If the NUC becomes unresponsive, see the manufacturer’s BIOS recovery instructions

Next Steps

After updating the BIOS: