Connect your Coldcard to your computer to approve the transaction details.
Caution: Unchained staff will never ask for your account password, 2FA code, hardware wallet PIN, or seed phrase. We will never ask you to send bitcoin to an unsolicited address.
We may ask for your email address, phone number, support PIN, or other information to verify your identity.
What you'll need
To securely sign a transaction from your Unchained vault, you'll need the following:
- Your Coldcard hardware wallet that is registered with the vault
- A power cord for the Coldcard
- A micro SD card 32 GB or less if you are using it air-gapped. Otherwise, follow the How to use a Coldcard with a USB cord guide to create a direct connection.
- A PC or Mac with USB ports to connect your hardware wallet
Video Guide
To sign a transaction using your Coldcard:
- Create a withdrawal or sell transaction.
- Can't find your transaction? Navigate to the vault you want to withdraw from and click View transaction.
- Can't find your transaction? Navigate to the vault you want to withdraw from and click View transaction.
- Select the key you want to sign with.
- Choose Coldcard as your hardware wallet.
- Select Download PSBT. This will save a .psbt file to your computer.
- Insert the microSD card into your computer's card reader.
- On your computer, transfer the .psbt file to your microSD card.
- Eject the microSD card from your computer and insert it into your Coldcard.
- Power on your Coldcard, enter your two-part PIN, and verify the anti-phishing words to unlock it.
- Select Ready To Sign on your Coldcard and select the .psbt file.
- Review the transaction details on your Coldcard.
- Your Coldcard will show you the amount, destination address, fees, and change address if applicable. Compare this information with the transaction details shown in your Unchained account.
- Your Coldcard will show you the amount, destination address, fees, and change address if applicable. Compare this information with the transaction details shown in your Unchained account.
- On your Coldcard, press OK to approve and sign the transaction. This will save an updated part.psbt file on your microSD card.
- Eject the microSD card from your Coldcard and insert it into your computer's card reader.
- On your Unchained account, click on Upload signed PSBT to open a file explorer window.
- Locate and upload the part.psbt file.
- Success!
- Once the transaction has two signatures, click Broadcast to send it to the bitcoin network. Upon broadcasting, the transaction will be irreversible.
Tip: If you’re actively experiencing signing issues, visit our troubleshooting guide to find a solution.