Download & Verify — DOOMSDAY-PREP.AI

Deployment procedure

Three steps to a drive you can trust

Every step below has a full walkthrough on this page. Total time: about 30 minutes, most of it waiting for the flash.

[01]

Download

Grab the compressed image and the checksum + signature files from your purchase library.

[02]

Verify

Check the SHA-256 sum and the PGP signature. If a single byte is off, you'll know — don't flash it.

[03]

Flash

Write the image to a 32GB+ USB 3 drive with Rufus, Etcher, or dd. Label it. Bag it. Done.

Integrity check

Verify every byte

A survival tool you can't trust is dead weight. Every release is published with a SHA-256 checksum and a PGP signature. Verify before you flash — especially if the image reached you on physical media or from a mirror.

Checksum compare

Computed a hash with your own tools? Paste both values — we'll compare them character-by-character. Nothing leaves your browser.

Official SHA-256 (from your purchase page) Your computed SHA-256

Hash a file in-browser

Drop a file to compute its SHA-256 locally in your browser. Fine for checksum files and docs; for the full multi-GB image, the command-line tools below are much faster.

▸ Drop file here or click to choose

Optional: expected hash (auto-compares when done)

Runs entirely offline in your browser — this page makes zero network requests with your file.

PowerShell — built in, no install

# In the folder containing the image:
Get-FileHash .\dd32-v1.0.img.xz -Algorithm SHA256

# Or with certutil (Command Prompt):
certutil -hashfile dd32-v1.0.img.xz SHA256

Copy the hash it prints into the compare tool above, next to the official value from your purchase page.

Terminal — built in

shasum -a 256 dd32-v1.0.img.xz

The 64-character string before the filename is your hash.

Terminal — built in

sha256sum dd32-v1.0.img.xz

# Or verify directly against our checksum file:
sha256sum -c SHA256SUMS
# → dd32-v1.0.img.xz: OK

PGP signature — proof it came from us

A checksum proves the file wasn't corrupted. The signature proves the checksum itself was published by Doomsday-Prep.AI and not swapped by someone in between. Our signing key fingerprint is printed on every purchase receipt:

KEY: ops@doomsday-prep.ai  //  FINGERPRINT: XXXX XXXX XXXX XXXX XXXX  XXXX XXXX XXXX XXXX XXXX

# 1. Import our public signing key (also included in your download):
gpg --import doomsday-prep-signing-key.asc

# 2. Confirm the fingerprint matches the one on your receipt:
gpg --fingerprint ops@doomsday-prep.ai

# 3. Verify the signed checksum file:
gpg --verify SHA256SUMS.sig SHA256SUMS
# → Good signature from "Doomsday-Prep.AI Release Signing"

# 4. Then verify the image against the now-trusted checksums:
sha256sum -c SHA256SUMS

Windows users: install Gpg4win and use the same commands in PowerShell, or right-click → "Verify" with Kleopatra. A "Good signature" from our key + a matching checksum = a byte-perfect, authentic image.

Write procedure

Flash the drive

Three tools, same result. Rufus is the easiest on Windows, Etcher is the easiest everywhere, dd is for people who alphabetize their go-bags. Use a quality 32GB+ USB 3 drive — flashing takes 10–25 minutes depending on the drive.

⚠ Read before flashing Flashing permanently erases everything on the target drive, and picking the wrong target can wipe the wrong disk. Unplug every USB drive you don't intend to erase before you start. Verify your download first — never flash an unverified image.

Difficulty: easy // Windows only // ~15 min

Get Rufus

Download the latest Rufus from rufus.ie. The portable version needs no install — fitting, for this product. Run it (allow the admin prompt).
Insert and select your USB drive

Plug in the target drive. Rufus lists it under Device. Confirm the size (~32GB) and drive letter match the drive you intend to erase.
Select the image

Click SELECT and choose dd32-v1.0.img.xz — Rufus reads compressed images directly, no need to extract. Boot selection will show the image name.
Leave the defaults alone

Partition scheme and target system are read from the image. Don't change them — the image already boots both BIOS and UEFI machines.
Start, confirm, wait

Click START, acknowledge the "all data will be destroyed" warning, and wait for the green READY bar. Don't unplug mid-write.
Eject and label

Safely eject the drive, physically label it (paint pen > sticker), and it's ready to boot. Windows may offer to "format" the drive's Linux partitions — always decline.

Difficulty: easiest // Windows, macOS, Linux // ~15 min

Get balenaEtcher

Download from etcher.balena.io for your OS and install/open it. On macOS it will ask for permissions to access removable drives — grant them.
Flash from file

Click Flash from file and pick dd32-v1.0.img.xz. Etcher handles the compressed image directly.
Select target

Click Select target and tick your USB drive. Etcher hides system disks by default and warns on anything unusually large — heed those warnings.
Flash and auto-validate

Click Flash! and enter your password if prompted. Etcher writes the image and then automatically re-reads the drive to validate the write — leave that on; it's a free integrity check.
Done

When it reports Flash Complete, eject, label, stash. Your OS may complain it "can't read" the drive — expected and fine; the partitions are Linux-formatted.

Difficulty: advanced // macOS & Linux // ~10 min

⚠ dd has no guardrails It will write to whatever device you name, including your system disk, without asking twice. Triple-check the target device before pressing Enter.

Linux

# 1. Identify the target. Plug the drive in, then:
lsblk
#    Find your USB by size, e.g. /dev/sdb — the whole disk, not /dev/sdb1

# 2. Make sure it isn't mounted:
sudo umount /dev/sdb?*

# 3. Decompress and write in one pipeline:
xz -dc dd32-v1.0.img.xz | sudo dd of=/dev/sdb bs=4M status=progress conv=fsync

# 4. Flush and eject:
sync && sudo eject /dev/sdb

macOS

# 1. Identify the target:
diskutil list
#    Find your USB by size, e.g. /dev/disk4 (external, physical)

# 2. Unmount it (not eject):
diskutil unmountDisk /dev/disk4

# 3. Write using the raw device (rdisk = much faster):
xz -dc dd32-v1.0.img.xz | sudo dd of=/dev/rdisk4 bs=4m

# 4. Eject when dd finishes:
diskutil eject /dev/disk4

No xz on macOS? brew install xz, or decompress first and dd the raw .img. Progress on macOS: press Ctrl+T in the terminal to make dd print status.

First boot

Booting from the drive

Plug the drive in, power the machine on, and immediately tap the boot-menu key for your manufacturer. Pick the USB entry (choose the "UEFI:" entry if you see both). If Secure Boot blocks it, disable Secure Boot in the firmware settings — the manual on your purchase page walks through it per vendor.

Manufacturer	Boot menu	Firmware setup
Dell	`F12`	`F2`
HP	`F9` (or `Esc`)	`F10`
Lenovo	`F12`	`F1` / `F2`
ASUS	`F8` / `Esc`	`F2` / `Del`
Acer	`F12`	`F2`
MSI / custom builds	`F11`	`Del`
Intel-era Mac	Hold `Option (⌥)` at chime	—

Tip: test-boot the drive on your own machine the day you flash it. A drive verified once and stored dry will boot years later — but verify it before you need it.

Three steps to a drive you can trust

Download

Verify

Flash

Verify every byte

Checksum compare

Hash a file in-browser

Flash the drive

Get Rufus

Insert and select your USB drive

Select the image

Leave the defaults alone

Start, confirm, wait

Eject and label

Get balenaEtcher

Flash from file

Select target

Flash and auto-validate

Done

Booting from the drive