A lost or stolen seed phrase should be treated as compromised. You need to replace the key entirely by conducting a key replacement.
Warning: The following steps impact the keys securing your bitcoin, and missteps can result in permanent loss of funds. If you'd like to speak one-on-one with a bitcoin expert to walk through this process, purchase a Premium Support session.
1. Acquire or reset a replacement device
If your seed phrase is lost or stolen, the best thing to do is purchase a replacement hardware wallet in order to generate a new key to perform a key replacement on the Unchained platform. It's generally best to purchase devices directly from the manufacturer. See the full list of hardware wallets that Unchained supports.
Optional: Factory reset an unused device
If you have an old hardware wallet (ensure it is unused and non-compromised before proceeding) that you want to use for replacing the compromised key, you can follow the manufacturer's respective instructions to perform a factory reset.
- Trezor: How to wipe your Trezor Model One
- Trezor: How to wipe your Trezor Model T
- Ledger: Reset Ledger Nano S (Plus) to factory settings
- Ledger: Reset Ledger Nano X to factory settings
Note: When you lose a seed phrase, you technically can use the hardware wallet associated with it to generate a new key and perform a key replacement. We advise against this in this guide because doing so is a technical process which done incorrectly could make you dependent on Unchained's key to recover your bitcoin.
2. Initialize device as new
Next, initialize the brand new (or newly-reset) device. This generates a new seed phrase which generates the public key that you will upload to the Unchained platform.
Note: Don't dispose of the corresponding hardware wallet for the compromised seed phrase at this stage. While not required, you may wish to use it to sign for the key replacement as described in step 4 below. This allows you to conduct a key replacement without depending on an Unchained signature.
Follow the guide from the manufacturer to set up the device as new:
- Trezor: How to setup your Trezor Model One
- Trezor: How to setup your Trezor Model T
- Ledger: Setup Ledger Nano S (Plus)
- Ledger: Setup Ledger Nano X
- Coldcard: How to setup a Coldcard
3. Conduct a key replacement
Follow our step-by-step guide to replace your key. It may help to open the guide in another browser tab while you perform the key replacement. Please contact us if you need any help with these steps.