Ownbit · Cold Wallet Guide
How to use the Ownbit Cold Wallet
The Cold Wallet feature turns a spare phone into a hardware wallet, so you can keep crypto fully self-custodied and air-gapped — with no extra hardware to buy.
Tap any screenshot to view it full size.Prepare two phones and install the latest Ownbit on both. Take one permanently offline — remove its SIM card and delete its saved Wi-Fi networks — and it becomes your Cold Wallet. Keep the other online as your Watch Wallet; this can be your everyday phone.
Create the Cold Wallet
Open Ownbit and tap Get Started
On the offline phone, open Ownbit and tap Get Started.
Choose the wallet type
On Add wallet, tap Create Personal Wallet for a personal cold wallet, or Create MultiSig Wallet for a multisig cold wallet. Already have a mnemonic? Tap Restore Wallet to import it instead.
Take the phone offline
On Protect your wallet you’ll see Hot Wallet and Cold Wallet. While this phone is online, Cold Wallet is greyed out — turn off Wi-Fi and mobile data (or switch on Airplane Mode) on this phone.
Select Cold Wallet
Once the phone is offline, the Cold Wallet option unlocks. Select Cold Wallet to continue.
Choose the mnemonic length
Select the number of mnemonic words — 12 or 24.
Cold Wallet ID is generated
Ownbit generates the Cold Wallet ID automatically.
Enable the coins you need
On the cold side, enable only mainnet / native coins. Tokens such as ERC20 / TRC20 are added later on the Watch Wallet, so the cold side doesn’t need them. Greyed-out coins don’t support cold wallet yet.
Done — your Cold Wallet is ready
The cold wallet is created and you land on its home page.
Write down the Cold Wallet’s mnemonic phrase and store it safely offline. If the phone is lost and you don’t have the mnemonic, the assets cannot be recovered. With the mnemonic, you can restore the wallet at any time.
Create the Watch Wallet & add coins
Open the cold wallet’s wallet page
In the cold wallet, tap the blue wallet bar to open its wallet home page.
Show the Watch Wallet QR code
Tap Setup Watch Wallet (or the wallet-management icon at the top right, then Setup Watch Wallet) to display the QR code for creating a Watch Wallet.
Add extra coins if needed
Switch the QR type to add other coins — the example adds SOL mainnet. BTC, ETH, TRX and BNB don’t need extra scanning; they’re already included in the Watch Wallet creation QR.
Scan on the online phone
On the online phone, open Add wallet and tap Scan to create Watch Wallet, then scan the QR codes from the cold wallet to create the Watch Wallet and add the coins.
Receive into the Watch Wallet
You’re now on the Watch Wallet home page and can receive funds. The cold wallet and watch wallet show the same receive address.
Send a transaction
Start on the Watch Wallet
Initiate the transaction on the Watch Wallet.
Enter the details
Enter the recipient address, amount and any other details.
Confirm
Review and confirm to send.
A signing QR code appears
The Watch Wallet shows a QR code that needs to be signed.
Scan it with the Cold Wallet
Use the offline cold-wallet phone to scan that QR code.
Open the signing page
The cold wallet opens its offline signing page.
Enter your password to sign
Enter the cold wallet password. After signing, a QR code with the signed result pops up.
Broadcast from the Watch Wallet
Scan the signed-result QR with the Watch Wallet to broadcast the transaction to the network.
See it on the home page
Back on the Watch Wallet home page, the transaction appears.
View the details
Tap the transaction to view its details.
In short: the Watch Wallet initiates, the Cold Wallet signs offline, and the Watch Wallet broadcasts. The cold phone stays permanently offline, so it never shows balances or history.
FAQ
The QR code is too large to display or scan
With some UTXO coins (BTC, DOGE, LTC, …) the signing QR can get too big when a transaction uses many UTXOs, pushing the byte size up. Lowering the amount usually fixes it — fewer UTXOs are selected, so the QR shrinks. You can also use Customize UTXO on the Watch Wallet’s confirmation page to pick fewer UTXOs.
Upgrading the Cold Wallet
Because the cold phone stays offline, it can’t update over the network. Recommended flow: back up the mnemonic (confirm it’s safely saved) → delete the Ownbit app → go online and install the latest Ownbit → go offline again and re-import the mnemonic to restore the cold wallet.