This comprehensive guide explains how to transform an old smartphone into a secure OwnBit cold wallet, eliminating the need for expensive hardware wallets while ensuring maximum security for your cryptocurrencies.
Preparing Your Cold Wallet Setup
Requirements
Two smartphones:
- Cold wallet device: Permanently offline (remove SIM card, delete Wi-Fi data).
- Observer wallet: Stays online for monitoring balances/transactions.
- Latest OwnBit app installed on both devices (download while online, then disable internet on the cold wallet).
Step 1: Creating the Cold Wallet
- On the offline device, open OwnBit and select "Create Wallet" (or "Import Wallet" if restoring).
- Choose "Personal Wallet" (for multisig, select "Multisig Wallet").
- Select "Cold Wallet" mode.
- Pick a 12 or 24-word seed phrase (backup securely—this is irreplaceable!).
Generate a Cold Wallet ID and enable mainnet coins (e.g., BTC, ETH).
- Note: Grayed-out coins lack cold wallet support.
⚠️ Critical: Never expose the cold wallet to the internet after setup.
Step 2: Setting Up the Observer Wallet
- On the cold wallet, navigate to the wallet homepage and tap "Create/Configure Observer Wallet".
Scan the displayed QR code with the online observer wallet phone to sync:
- Select specific coins/tokens (e.g., TRX, ERC-20 tokens) during scanning.
- The observer wallet now displays balances and receives funds (addresses match the cold wallet).
Step 3: Sending Transactions Securely
Process Overview
- Observer Wallet: Initiate the transaction (enter recipient/amount).
- Cold Wallet: Scan the observer’s signature QR code to approve offline.
- Observer Wallet: Scan the cold wallet’s signed QR to broadcast the transaction.
👉 Learn advanced cold wallet strategies here
Troubleshooting
Oversized QR Codes: Common with UTXO coins (BTC, LTC). Fixes:
- Reduce the transaction amount.
- Manually select fewer UTXOs via "Custom UTXO" in the observer wallet.
Step 4: Cold Wallet Maintenance
Upgrading the App
Since the cold wallet can’t update online:
- Backup your seed phrase.
- Uninstall OwnBit, then reinstall the latest version.
- Re-import the seed phrase (offline) to restore the wallet.
FAQs
Q1: Can I use the same phone for cold and observer wallets?
No—the cold wallet must stay permanently offline to prevent hacking risks.
Q2: What if my cold wallet phone breaks?
Your seed phrase is the backup. Import it into a new offline device.
Q3: Are ERC-20 tokens supported?
Yes, but add them only in the observer wallet; the cold wallet handles mainnet approvals.
Q4: How do I verify a transaction’s status?
Check the observer wallet or blockchain explorers (e.g., Etherscan for ETH).
👉 Explore crypto security tools
Conclusion
OwnBit’s cold wallet leverages old smartphones for bank-grade security without hardware costs. By following this guide, you ensure:
- Zero online exposure for private keys.
- Full control over transactions via offline signing.
- Scalability for multiple cryptocurrencies.
For further reading, see our guide on multi-signature wallets or decentralized storage solutions.
Disclaimer: Always test small transactions first and double-check addresses.