How to Boot DoomsDay USB

1. Insert the DoomsDay USB into your computer.
2. Power on (or restart) your PC.
3. Immediately start pressing the Boot Menu key for your system:

  • F12 – Dell, Lenovo, Acer, Toshiba, most laptops
  • ESC or F9 – HP
  • F8 – Asus
  • F10 – older models
  • F2 or DEL – Sometimes for BIOS then select Boot Menu
4. Select your USB drive from the boot menu.
Tip: If you miss the key, restart and try again. Timing is important!

Disable Secure Boot if Needed

If your computer doesn't boot from DoomsDay USB:
1. Restart your PC and press F2 (or DEL) to enter BIOS/UEFI.
2. Find Secure Boot (usually under "Boot" or "Security" tab).
3. Set Secure Boot to Disabled.
4. Save changes (F10), then exit.
5. Try booting again from USB.
Note: Secure Boot can block non-certified OS. Disabling it is safe and reversible.

Important: BitLocker Users

If you use BitLocker on your Windows drive:

  • Before booting with DoomsDay USB, save your BitLocker Recovery Key.
  • Backup your key to a USB, cloud, or print it out.
  • If possible, temporarily disable BitLocker from Windows settings to avoid lockout.
Warning: Without your recovery key, you could lose access to your Windows files!

What is DoomsDay USB?

DoomsDay USB is a portable Linux operating system.

  • 400+ pre-installed survival manuals, always offline.
  • Offline AI assistant support: download and run open-source models locally.
  • Privacy-first: nothing sent online by default.
  • Essential tools and knowledge ready to use, anywhere, anytime.
Your all-in-one private survival toolkit.

Which Image to Download: GPT

Choose the GPT version of DoomsDay USB if your PC uses UEFI firmware (most computers since 2015):

  • Most modern laptops and desktops support UEFI/GPT.
  • UEFI often shows a graphical BIOS interface with mouse support.
  • Secure Boot is available only on UEFI systems.
  • Windows installed in UEFI mode always uses GPT partitioning.
  • For best compatibility with new hardware, GPT is recommended.
How to check?
In BIOS, look for “UEFI” options or “Boot Mode: UEFI.” If unsure, try GPT first—if your PC does not detect it, use MBR.

How to use your ISO: After downloading, use balenaEtcher to safely write the ISO to your USB stick. Just open Etcher, select your ISO, choose your USB, and click "Flash"!

Which Image to Download: MBR

Choose the MBR version of DoomsDay USB if your PC uses legacy BIOS (older computers, pre-2012):

  • Legacy BIOS usually shows a text-only (blue or gray) BIOS screen with keyboard navigation only.
  • If your PC cannot boot the GPT version, use the MBR version instead.
  • Windows installed before 2015 is often on MBR/Legacy BIOS systems.
  • Some older or refurbished laptops require MBR for booting from USB.
  • For maximum compatibility with very old hardware, choose MBR.
Tip: You can always make both USBs and try them—no risk to your PC.

How to use your ISO: After downloading, use balenaEtcher to safely write the ISO to your USB stick. Just open Etcher, select your ISO, choose your USB, and click "Flash"!