XBT cold storage: a SeedSigner setup for Bitcoin BLAKE2b
Keep your XBT keys on a device that never touches the internet. This guide builds a SeedSigner, a small open-source signing device made from off-the-shelf parts, running community firmware that understands the XBT chain. Your coins are watched and sent from the Sparrow BLAKE2b build on your computer, and every send is signed on the SeedSigner by scanning QR codes. No cables, no Wi-Fi, no seed on your computer.
Read this first. The XBT firmware and wallet forks are community software, new, and unaudited. The SeedSigner build uses published development signing keys, so it shows warnings. Test every step with a small amount before you move real money. xbt.live doesn't make or sell any of this.
Which coins are you protecting?
| Your XBT came from | Replay risk | What to do |
|---|---|---|
| Bought on an exchange after Sept 1, 2026 | None. These coins only exist on XBT. | Follow this guide. Withdraw to your new SeedSigner wallet. |
| Mined on XBT | None. | Follow this guide. Point pool payouts at an address from the SeedSigner wallet. |
| Pre-fork bitcoin you held before block 961,632 (Aug 8, 2026) | Yes. The same coins exist on both chains, and a normal signature is valid on both. | Split first. See Pre-fork coins below. |
How replay protection works
XBT and Bitcoin share all history up to block 961,632, so a normal signature works on both chains. XBT added an opt-in signature flag, SIGHASH_UNIFIED (0x20, so a normal SIGHASH_ALL becomes 0x21). A transaction signed with it is valid on XBT and invalid on Bitcoin. The wallets and firmware in this guide use it. Plain Bitcoin wallets and stock hardware wallet firmware do not.
Parts list
| Part | Notes | Approx. |
|---|---|---|
| Raspberry Pi Zero v1.3 | The version without Wi-Fi or Bluetooth. Add a header if it doesn't come with one. | $15–25 |
| Waveshare 1.3" LCD HAT (240×240) | The standard SeedSigner screen with joystick and buttons. | $15 |
| Pi Zero camera (OV5647) | Must come with the narrow Pi Zero ribbon cable. | $10–15 |
| MicroSD card, 4–32 GB | Holds the firmware only. Your seed is never saved to it. | $6 |
| Casino dice | To generate your seed with real randomness. | $8 |
| Steel seed backup | Fire- and water-proof backup of your 24 words. | $20–40 |
Links may earn xbt.live a small commission at no cost to you. Buy the Pi and camera from any store you trust.
Step by step
- Flash the XBT firmware. Download the image from privkeyio/seedsigner-os, check its hash against the release page, and write it to the microSD card with balenaEtcher or Raspberry Pi Imager.
- Assemble. Clip the screen onto the Pi's header, connect the camera ribbon, insert the card, and power it from any USB charger. It never needs a data cable.
- Make a brand-new seed with dice. Choose Tools → New seed → Dice rolls and roll 99 times for 24 words. Never reuse your bitcoin seed: a separate seed keeps the two chains apart for good.
- Back it up. Write the 24 words on paper, then stamp them into steel. No photos, no cloud, no typing them anywhere.
- Install the Sparrow BLAKE2b build on your computer from paulscode/sparrow. Point it at an XBT Electrum server (a BLAKE2b-aware electrs or Fulcrum fork). Your own node is best.
- Export the watch-only wallet. On the SeedSigner, choose Export xpub → Native SegWit → Sparrow. In Sparrow, New wallet → Airgapped hardware wallet → SeedSigner → Scan. Sparrow can now see your balance but can't spend.
- Receive a small test amount. Copy a receive address from Sparrow and confirm it on the SeedSigner (Scan → address QR) before sending anything to it.
- Do a test send. In Sparrow, create a transaction and show it as a QR code. Scan it with the SeedSigner, check the amount and address on its screen, and confirm it signs with unified sighash. Scan the signed QR back into Sparrow and broadcast.
- Check it on the explorer. Look the transaction up on an XBT explorer. Once the test send confirms, move the rest.
Pre-fork coins: split before you spend
If your bitcoin was in a wallet before block 961,632, you also have the same amount of XBT at the same addresses. Spending one copy carelessly can move the other. The safe order, per the Knots release notes:
- Spend the XBT copy first, using a wallet that signs with unified sighash (Knots, the Sparrow BLAKE2b build, Shrike, or the SeedSigner firmware above). Send it to an address in your new XBT-only wallet.
- Wait for it to confirm on XBT. Now the XBT copy has moved and can't be replayed onto Bitcoin.
- Your bitcoin is untouched and can be spent normally on Bitcoin later.
Doing it the other way round (spending bitcoin first with a normal wallet) can broadcast the same transaction on XBT too. Avoid cross-chain "swap" or "splitter" tools with no review history.
Scam warning: nothing needs to be "claimed." Any site, app or person asking for your seed phrase or private key to claim, unlock or split fork coins is a scam. Your seed goes into the SeedSigner and nowhere else.
Simpler alternatives
- Air-gapped laptop: the Sparrow BLAKE2b build on an old laptop that never goes online, signing with QR codes or a USB stick.
- Coldcard or Trezor: community firmware forks with unified sighash exist, also unaudited. Flashing them changes your device; don't do it on the one that holds your bitcoin.
- Knots BLAKE2b wallet: your own full node's wallet supports unified sighash directly.
All of these are listed on our Tools page and the community awesome-bitcoin-blake list.
Found a step that's wrong or out of date? Email hello@xbt.live and we'll fix it.
This guide is for education and is not financial or security advice. Community firmware and wallets are unaudited; you are responsible for your keys. Test with small amounts first.