After adding your Coldcard to Casa App, you can use your Coldcard to perform a health check on the device.
The steps detailed below show how to perform a Health Check of your Coldcard in Casa App (to ensure that it’s been properly added and available for signing outgoing transactions when needed).
If you haven’t added your Coldcard to Casa yet, please see our article Adding Coldcard to Casa App.
If you want to learn how to sign a transaction with Coldcard, see Signing a Transaction with Coldcard.
When performing a health check, you will need:
- Coldcard device
- A laptop or desktop computer
- Micro SD card
- Micro SD card adapter (if your computer does not have a micro SD card slot)
First, initiate a Health Check from within Casa App.
Next, check your email inbox for an email from Casa with a link. Clicking that link will initiate the health check process.
Physically insert your SD card into your computer (you may need an adapter for this step).
When you click the link, you’ll be prompted to download a .txt file onto your computer. Once the file is downloaded, drag and drop the file onto the Coldcard’s SD card.
Next, take the SD card out of your computer and insert it into your Coldcard.
When your Coldcard is powered up and unlocked with your PIN code, navigate to:
Advanced > MicroSD Card > Sign Text File
Click “Ok” to export the signed text file to the SD card.
Now that the signed health check file is copied to the SD card, you’re ready to transfer the file back to your computer to complete the health check verification process.
Remove the SD card from the Coldcard and insert it into your computer.
Back at the Casa API, click “Next,” then drag and drop the new file with a name that ends in "signed.txt" into the window when prompted.
If the signature is successfully verified, you'll see a success message - you're done! If you see an error then you may have added the wrong file or you may be using a device that is not a part of your current key set.