A fingerprint when it pertains to your hardware wallet refers to a private key. Just like each private key is unique, each private key also has a unique fingerprint associated with it. The root fingerprint error ultimately means the incorrect private key is attempting to approve activity on behalf of another private key. On our platform, actions include performing a Key check, signing a transaction, or confirming an address.
Two frequent causes for the fingerprint error are, having the wrong device plugged in or having a passphrase enabled on your device. The solution then is to confirm you have the correct device plugged in (with the right seed loaded) or make sure when prompted by Trezor bridge to enter your passphrase that you enter it correctly.
Steps for devices with the passphrase enabled:
1. Open the Trezor suite and plug in your Trezor.
2. Type in your pin > Type in your passphrase > and go through the prompts.
3. Retype in your passphrase and keep the Trezor suite open and device connected.
4. Log in to your Unchained account and proceed to perform the desired action (key check, sign, or confirm an address.)
Following the steps above, you will now be able to add your passphrase through the Trezor bridge and match the correct private key, the "fingerprint," and conduct the desired action.
Disclaimer Warning: Adding a passphrase to your wallet will essentially add an unrecoverable "25th word." If you forget this passphrase, you may permanently lock yourself out of your bitcoin. A passphrase is different from your device's pin and is optional.
For the people who want to add the key with the hidden passphrase to their UC account:
You can add keys with a passphrase enabled onto the Unchained platform. If you set up the key with a passphrase using the Trezor suite, follow these steps before adding the key.
1. Open up the Trezor suite and connect the device.
2. Once connected, you will be prompted to type in your passphrase.
3. With the Trezor suite open, and the device connected, navigate to your Unchained account and add the new key.