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Security Masterclass Hardware Wallets September 9, 2026

How to Safely Claim Blake2B Bitcoin Fork Coins: Shrike Wallet & Coldcard Setup Guide

If you held Bitcoin in self-custody prior to the August 2026 hard fork, you technically own an equivalent quantity of the Blake2B (BTC2B) fork coin. The identical Unspent Transaction Outputs (UTXOs) exist on both ledgers. In this step-by-step technical guide, learn how to import your emptied pre-fork wallet into Shrike (the Blake2B fork of Sparrow), flash custom firmware onto an old Coldcard, and transfer your claimed fork coins into offline cold storage without risking your real Bitcoin.

Claiming Blake2B Fork Coins: Shrike and Coldcard Pipeline Diagram
The Three-Stage Claiming Protocol: Wallet Drainage on Bitcoin, Shrike Software Coordinator, and Coldcard Hardware Isolation.
Critical Risk Assessment: When in Doubt, Do Nothing

Currently, the Blake2B fork coin trades around $300, while real Bitcoin trades near $80,000. You are dealing with experimental, unvetted open-source forks and third-party nodes. Never risk thousands of dollars in pristine Bitcoin for a few hundred dollars in fork tokens.

If you do not have advanced familiarity with UTXO coin control, seed phrases, and firmware flashing, the safest and smartest decision is to simply do nothing. Your real Bitcoin will remain safe as long as you do not expose private keys or sign reckless transactions.

The Mandatory Security Prerequisite: Empty the Original Wallet

Before you even think about downloading fork software or entering private keys, you must follow the strict security protocol established in our Replay Protection & UTXO Splitting Guide:

  1. Generate a Fresh Bitcoin Wallet: Set up a brand-new, securely initialized hardware wallet with completely separate 12 or 24 recovery words.
  2. Execute Replay-Protected Sweeps: Mix post-fork tainted Bitcoin inputs with your pre-fork UTXOs so that the transaction is only valid on the Bitcoin network and invalid on the Blake2B chain.
  3. Verify Zero BTC Balance: Ensure that your old wallet has exactly 0.00000000 BTC remaining on the real Bitcoin blockchain.

Once your real Bitcoin is physically and cryptographically isolated in your new wallet, the old seed phrase holds only the ghost UTXOs on the Blake2B chain. If that old seed phrase is ever compromised or typed into software, zero real Bitcoin is exposed.

Step 1: Download and Verify Shrike Wallet

To interact with the Blake2B ledger, we use Shrike, an open-source fork of Sparrow Wallet developed by Kyle Santiago. It features an inverted visual color scheme and is pre-configured for the Blake2B network parameters.

Cryptographic Verification Steps:

  • Download the latest Windows installer (.msi) from the official GitHub releases.
  • Download SHA256SUMS, the detached GPG signature file SHA256SUMS.asc, and the developer's public signing key.
  • Launch Shrike, navigate to Tools → Verify Download, and load the respective hash and signature files.
  • Verify that the signature confirms a valid hash signed by Kyle Santiago before running or configuring the software.

Step 2: Connect Shrike to a Blake2B Electrum Server via Tor

Unlike the main Bitcoin network which has thousands of public nodes, the Blake2B ecosystem is nascent. You will need to connect Shrike either to your own self-hosted Blake2B Bitcoin Knots node or to a trusted community Electrum server over Tor.

  1. In Shrike, navigate to File → Settings → Server.
  2. Select Private Electrum and paste the Blake2B .onion address into the URL field.
  3. Click Test Connection. Shrike will automatically boot the internal Tor daemon, negotiate circuits, and establish a secure TCP connection to the Electrum backend.
  4. Once connected, the bottom-left status indicator will turn blue/green, confirming live network synchronization.

Step 3: Import the Emptied Seed as a Software Wallet

With the coordinator connected, you can now import your previously drained seed phrase to discover your pre-fork UTXOs:

1. Go to File → New Wallet, enter a descriptive label (such as Blake2B-Claim), and select New or Imported Software Wallet.

2. Choose Mnemonic (BIP39) and enter the 12 or 24 words from your drained Bitcoin wallet (along with any passphrase if previously configured).

3. Select the matching derivation script (such as Native SegWit - P2WPKH) and click Import.

4. Shrike will scan the Blake2B blockchain and populate your historical transaction history along with your claimable UTXO balances.

Step 4: Flash Custom Fork Firmware on Coldcard

Holding coins in an online software wallet on a desktop computer leaves them vulnerable to hot wallet malware. You can repurpose an older hardware device, such as a Coldcard MK4, MK5, or Coldcard Q (or alternatively a SeedSigner), to serve as a dedicated cold storage signing device for the fork coin.

Coldcard Firmware Flashing Procedure:

  1. Download the custom firmware file (MK_coldcard.dfu) from the fork developer repository onto a clean microSD card.
  2. Insert the microSD card into the Coldcard and power on the device with a secure power-only cable or battery pack.
  3. Navigate to Advanced/Tools → Upgrade Firmware → From MicroSD.
  4. Select the .dfu file and confirm the upgrade. When the Coldcard displays the "Danger: Custom Firmware" prompt, proceed with the checkmark.
  5. Once flashed, perform a full device wipe/factory reset and generate a fresh, independent seed phrase exclusively for your Blake2B cold storage.

Step 5: Export Descriptor & Pair Coldcard with Shrike

To allow Shrike to construct partially signed transactions and watch your cold storage balance without exposing private keys:

  1. On the Coldcard, navigate to Advanced/Tools → Export Wallet → Sparrow.
  2. Confirm the export. The Coldcard writes a JSON wallet descriptor file to the microSD card.
  3. Eject the microSD card and insert it into your computer.
  4. In Shrike, click File → Import Wallet → Coldcard → Import File.
  5. Select the exported JSON descriptor file. Shrike will generate a watch-only hardware wallet profile (e.g., Coldcard MK5).

Step 6: Transfer Fork Coins from Software Wallet to Cold Storage

The final step is moving your claimable Blake2B coins out of the temporary hot software wallet into your hardened Coldcard hardware wallet:

  1. In your Coldcard MK5 wallet tab in Shrike, go to the Receive tab and copy a fresh receiving address.
  2. Switch to your Blake2B-Claim software wallet and navigate to the Send tab.
  3. Paste the hardware receive address, enter the amount (or send a small test transaction of 15,000 Blakes first), and set an appropriate fee rate.
  4. Click Create Transaction → Finalize for Signing.
  5. Since this is a software wallet, click Sign and then Broadcast Transaction.
  6. Check your Coldcard wallet tab: the incoming transaction will appear in the mempool and confirm on the Blake2B blockchain.

Your Blake2B fork coins are now fully secured in offline hardware cold storage, and your real Bitcoin remains completely untouched and safe in your primary wallet.

Watch ForrestHODL's full video walkthrough on Shrike configuration, Coldcard flashing, and cold storage transfers.

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