How to Boot DoomsDay USB

  1. Insert the DoomsDay USB into your computer.
  2. Power on (or restart) your PC.
  3. Immediately press your Boot Menu key:
    • 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

  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

  • 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?

  • 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.

How to Check UEFI/GPT or Legacy BIOS/MBR

On Windows:
  • Press Win + R, type msinfo32, press Enter.
  • In System Information, check BIOS Mode:
    • UEFI = Use the GPT version
    • Legacy = Use the MBR version
  • To check your disk partition style:
    Press Win + X → Disk Management.
    Right-click your main disk → Properties → Volumes tab → check Partition style ("GUID Partition Table (GPT)" or "Master Boot Record (MBR)").
Tip: UEFI/GPT is standard on most PCs since 2015.
If unsure, try GPT first. If it doesn't boot, use MBR.

Which Image to Download: GPT

  • Choose the GPT version if your PC uses UEFI firmware (most since 2015).
  • 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 if your PC uses legacy BIOS (older computers, pre-2012).
  • Legacy BIOS shows a text-only (blue/gray) BIOS screen with keyboard navigation.
  • If your PC cannot boot the GPT version, use the MBR version.
  • Windows installed before 2015 is often on MBR/Legacy BIOS systems.
  • Some older/refurbished laptops require MBR for USB booting.
  • For max 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"!