Introduction
Congratulations on taking the first step toward securing your Bitcoin through self-custody! This guide is designed for beginners and will walk you through setting up a ColdCard hardware wallet—an offline, air-gapped solution for safely storing and transacting Bitcoin.
Materials You’ll Need
- ColdCard hardware wallet
- MicroSD card (for offline transaction signing)
- 9V battery adapter (optional power source)
- USB-to-Micro-USB cable
- Metal backup tool (e.g., CypherWheel or Billfodl for seed phrase storage)
- Desktop or laptop computer
Step-by-Step Setup
1. Purchase Your Hardware Wallet
The ColdCard comes in a tamper-proof blue bag with a unique serial number. Keep this number private—it identifies your specific device. Inside, you’ll find:
- The ColdCard device
- A blank backup card (for recording your recovery phrase)
👉 Get your ColdCard wallet here
2. Power On and Connect
- Use the Micro USB cable to connect the ColdCard to a computer or power source.
- Ensure the device remains powered throughout setup.
3. Set Up Your PIN
- Navigate the menu using the 5 (up) and 8 (down) keys.
Choose a two-part PIN (each part 2–6 digits).
- The first part determines anti-phishing words—write these down and store them securely.
4. Create a New Wallet
- Select “New Wallet” to generate a BIP39-compliant wallet.
The ColdCard will produce 24 seed words from a standardized list.
- Write them in order on the backup card.
- Verify the words when prompted.
5. Backup Your Seed Phrase
- Use a metal backup tool (e.g., CypherWheel) to protect against physical damage.
- Store backups in multiple secure locations.
👉 Explore metal backup options
Signing Transactions Offline
Method: Air-Gapped Signing (MicroSD Card)
1. Prepare Transaction in Electrum
- Install Electrum and create a SegWit (bc1) wallet.
- Enter recipient address and amount under the “Send” tab.
2. Export Transaction
- Select “Export For Hardware Device” (ensure “xpubs” is included).
- Save as a .PSBT file to the MicroSD card.
3. Sign with ColdCard
- Insert the MicroSD card into the ColdCard.
- Select “Ready to Sign” and approve the transaction.
- The signed file (-final.txn) will save to the card.
4. Broadcast Transaction
- Reinsert the MicroSD into your computer.
- Load the signed file in Electrum via Tools > Load Transaction > From File.
FAQ
Q: Why use an air-gapped wallet?
A: Air-gapped wallets never connect to the internet, drastically reducing hacking risks.
Q: Is Electrum the only compatible software?
A: No! Sparrow Wallet and Wasabi also support ColdCard.
Q: Can I recover my wallet if lost?
A: Yes—use your 24-word seed phrase on any BIP39-compatible wallet.
Conclusion
Self-custody puts you in full control of your Bitcoin. By following this guide, you’ve learned to:
- Set up a ColdCard wallet.
- Safely store your seed phrase.
- Sign transactions offline.
Welcome to financial sovereignty!