The following list of USB BIOS boot settings and options have been thoroughly tested with various Linux USB installs. There may be others, but this is meant to be a simple checklist to familiarize you with the boot options and which ones to use. Be sure to check back often as I will be constantly adding new information to this list over time.
Newer UEFI or BIOS USB Boot Settings
Many newer computers automatically detect the USB device as a hard drive. In this case, you can simply press a specific key (F2, F10, F11, or ESC) during system POST to access the "Boot Menu." Select your USB DISK from the Boot Menu and resume startup.
Steps to Access Boot Menu:
- Restart your computer.
- Press the appropriate key (F2, F10, F11, or ESC) during POST.
- Select the USB drive from the Boot Menu.
- Resume startup.
Older USB BIOS Boot Settings (USB-HDD)
If your system is older or uses a simplified BIOS, you may not have a Boot Menu option. In this case, you will need to make the system detect and boot your USB device by changing the settings in the BIOS.
Preferred Boot Method:
- USB-HDD: Generally speaking, if your system BIOS supports the USB-HDD boot option, it should boot Linux from a large capacity USB flash drive. (A BIOS that supports USB-HDD automatically detects the geometry of the USB flash drive.)
Alternative Methods:
- USB-ZIP: May work, but you might need to modify the drive geometry to match how the BIOS sees the device.
- USB-FDD: Unsupported.
In summary: Generally speaking, if your system BIOS supports the USB-HDD boot option, it should boot Linux from a large capacity USB flash drive. (a BIOS that supports USB-HDD automatically detects the geometry of the USB Flash drive)
On older systems that do not support USB-HDD boot, the USB-ZIP option can be used. However, you'll need to modify the drive geometry to match how the BIOS has been hard coded to see the device. Essentially tricking how the BIOS sees the device. This usbkey.txt syslinux documentation mentions a very good method to use for modifying flash drive geometry.
Exception: The USB-ZIP boot option may allow you to boot some larger capacity flash drives without drive geometry modification, if your flash drive is listed as a selectable hard drive, under boot priority. (Common on systems using an Award-Phoenix BIOS)
Steps to Configure Older BIOS:
- Enter BIOS Setup:
- Restart your computer.
- Press the appropriate key (Del, F2, F10, Esc, or F12) to enter BIOS setup.
- Change Boot Order:
- Locate the boot order settings (usually under "Boot," "Advanced BIOS Features," or similar).
- Set USB-HDD as the first boot device.
- Save and Exit:
- Save changes and exit BIOS setup (usually by pressing F10 and confirming).
Exception for USB-ZIP Booting:
The USB-ZIP boot option may allow you to boot some larger capacity flash drives without drive geometry modification if your flash drive is listed as a selectable hard drive under boot priority. This is common on systems using an Award-Phoenix BIOS.
Other BIOS USB Booting Tips
- First Boot Device: If your BIOS lists the USB memory stick as a hard drive, select it as the 1st boot device.
- Remove Conflicting Boot Options: Remove other USB boot options from the boot priority list when attempting to boot from USB-ZIP or USB-HDD to avoid conflicting startup cues.
- Filesystem and Active Partition: The filesystem used may also affect the BIOS's ability to detect and boot the drive. If a FAT file-system doesn't work, try FAT32. The partition must also be active or the device will not boot.
- BIOS Updates: Keep an eye out for BIOS updates from your board manufacturer. There may be a bugfix for your motherboard related to the problem.
- Recent BIOS Support: Through experience, most "recent" Award/Phoenix and AMI BIOS's can generally support USB boot.
USB Booting Troubleshooting
- USB Drive Not Recognized: Ensure the USB drive is properly formatted and contains a bootable image. Tools like Rufus can help create bootable USB drives.
- BIOS Not Showing USB Option: Try different USB ports. Ensure the USB drive is plugged in before powering on the system.
- Legacy Boot and Secure Boot: If you’re having trouble, you may need to enable Legacy Boot and disable Secure Boot in BIOS settings.
- Revert Changes: If needed, revert BIOS boot settings to default by selecting the appropriate option in BIOS setup.
By following these guidelines, you can effectively configure your system to boot from a USB drive, allowing for a wide range of applications from OS installations to system recovery.
If you still need more help, feel free to check out our USB BIOS Booting Tips section.