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Do not use an unexpected Coldcard alert as your trust anchor. Leave its links unopened, go independently to a known COLDCARD or Coinkite address, and verify any notice, destination, and firmware file there. If firmware is involved, check the exact device model and release family, verify the OpenPGP signature on signatures.txt, and compare a locally calculated SHA-256 hash with the value in that signed manifest before installing anything.
Why a convincing alert is still unverified
A message can display familiar branding, a plausible sender name, urgent wording, and a button that appears to lead to a genuine update. None of those features proves that its link is safe. The link destination, the downloaded file, and the request for information must each be checked through a route you establish yourself.
That matters especially for a hardware wallet. A fraudulent page may try to collect a seed phrase, passphrase, private key, wallet backup, or dice-roll sequence. A malicious firmware file could also undermine the device even when the message looks like a routine security notice. Treat the alert as a lead about something to investigate, not as evidence that the alert itself is authentic.
The COLDCARD About page states: “Before downloading firmware, confirm that the browser address is on an official domain and verify the download using the firmware verification procedure.” Follow that rule before downloading, signing in, entering information, or connecting a storage card.
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Start from an official address you enter yourself
Close the alert or leave it open without selecting its buttons. Use a bookmark you created from a previously verified visit, or type the address manually. The official properties identified by COLDCARD and Coinkite are:
| Purpose | Official property | Use it for |
|---|---|---|
| COLDCARD website and documentation | coldcard.com | Starting point for product information, documentation, and links to current notices or downloads. |
| Company information | coinkite.com | Confirming the company’s own information and support boundaries. |
| Store | store.coinkite.com | Purchases only; it is not a reason to follow an alert’s payment or verification link. |
| Security notices and company updates | blog.coinkite.com | Checking whether a claimed security announcement appears through the company’s published channel. |
| Firmware source | github.com/Coldcard/firmware | Reviewing the official firmware source repository. Use the documented download and verification process for installation files. |
Check the address bar, not just the page design. Look at the complete host name and spelling before downloading. A lookalike domain, an extra word, a substituted character, or a different top-level domain is not made official by a copied logo. If the page was reached from the alert, close it and re-enter the official route manually.
A repeatable verification workflow
1. Pause and preserve the alert as evidence
Do not click “verify,” “secure account,” “download update,” or a similar call to action. Do not reply with personal information. Record the visible sender, subject, date, and wording if you need to report the attempt, but do not treat the sender label as authentication.
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If a message says an account or device will be disabled within minutes, that pressure is a reason to slow down. Genuine urgency can still be investigated from an independently entered official address.
2. Reach the notice through the official site
Open coldcard.com or another official property listed above by using your independent route. From there, follow the site’s current navigation to security notices or documentation. Do not paste the alert’s URL into the browser to “compare” it; that still gives the unverified link control over the first page you inspect.
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If the alert claims to report a vulnerability, maintenance event, or required action, look for the same information in the official notices. An absence of a matching notice does not by itself prove fraud, but it means the message has not been corroborated and should not be used to justify a download or disclosure.
3. Inspect the destination before downloading
For every page you open from the official route, recheck the address bar before selecting a download. The page should remain on an official COLDCARD or Coinkite property, or on the explicitly identified official firmware repository. Redirects, shortened links, embedded login forms, and requests to move the conversation to an unfamiliar support channel are reasons to stop.
Do not enter a wallet secret to unlock a download. A page that asks for a seed phrase, passphrase, private key, dice-roll sequence, or wallet backup file is outside the support boundary described by Coinkite.
4. Match the firmware to the exact device
If the alert points to firmware, open the official firmware downloads page independently. Identify the exact COLDCARD model and the release family shown in the listing. The listings distinguish standard, Edge, and older-model releases; a similar-looking filename is not sufficient evidence of compatibility.
| Check | What must match | What not to do |
|---|---|---|
| Device model | The model printed on or selected for your actual COLDCARD. | Do not assume that a file for a newer or similarly named model will work. |
| Release family | The family identified by the official listing for that model, such as standard, Edge, or an older-model track. | Do not choose solely because a filename contains a familiar version number. |
| Download source | The file obtained through the independently opened official download route. | Do not use the attachment or download URL supplied by the alert. |
The firmware help page, written by the Coinkite Team and reviewed July 17, 2026, gives the direct instruction: “Use only an official firmware file intended for your model.” If you cannot establish both model and release family, do not continue.
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5. Download the complete file and signed manifest
Use the official listing to obtain the full firmware file and its signatures.txt manifest. Keep both files together. Do not rename them in a way that makes their relationship unclear, and do not substitute a manifest supplied by the alert’s sender.
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6. Verify the OpenPGP signature on signatures.txt
Use the OpenPGP verification procedure documented by COLDCARD. The signature check answers: “Was this manifest signed by the expected official signing key, and has the signed content remained intact?” Review the verifier’s result rather than relying on a downloaded key file or a green-looking web page.
- A valid result should identify the expected signing key and report that the signature is good.
- An unknown key, an invalid signature, a missing signature, or a warning you cannot explain is a failure, not a pass.
- Do not treat a signature on the firmware file itself as a replacement for checking the manifest if the official procedure tells you to verify
signatures.txt.
If your OpenPGP tool cannot validate the signature, stop and obtain the current verification instructions from the independently opened official documentation. Do not disable warnings or accept an unverified key merely to make the process complete.
7. Calculate and compare the firmware SHA-256 hash
After the manifest’s signature is valid, calculate the SHA-256 hash of the firmware file locally with a trusted hashing utility. Compare the complete value, character for character, with the firmware hash recorded in the signed manifest.
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- Matching values establish that the file you downloaded is the same byte-for-byte file identified by the signed manifest.
- A mismatch means the file is not the one identified by the manifest. Do not install it, even if the filename and version appear correct.
- Do not compare only the first or last few characters, and do not copy a hash from the alert instead of the signed manifest.
Both checks are required: the OpenPGP signature authenticates the manifest, and the SHA-256 comparison connects that authenticated manifest to your local firmware file. Passing only one check leaves an unresolved gap.
Installing verified firmware without confusing the transfer method with proof
Only after the model, release family, manifest signature, and local hash all check out should you use the documented upgrade procedure. A microSD card is one documented way to transfer firmware to a COLDCARD. It is a transfer medium, not evidence that the alert, website, or file is legitimate.
- Use a microSD card or another installation medium supported by the current official upgrade instructions.
- Copy the already verified firmware file according to those instructions. Do not copy an unverified attachment first and plan to “check it later.”
- Start the upgrade from the device’s documented menu and confirm that the device identifies the intended model and release family.
- If the device reports an incompatibility, signature problem, unexpected filename, or other error, stop. Return to the independent official download route instead of trying alternate files from the alert.
- Keep the manifest and your verification records until the upgrade has completed and the device behaves as expected.
Compatibility details and menu labels can change as firmware evolves. Use the current upgrade documentation reached from the official site rather than relying on an old screenshot or instructions embedded in an unsolicited message.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Secrets that purported support must never request
Coinkite’s stated support boundary is unambiguous: support will not ask for seed words, passphrases, dice-roll sequences, private keys, or wallet backup files. Never disclose any of these to a person who claims to be support, security staff, a developer, or an incident responder.
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- Seed words: Never type or photograph them for a support ticket.
- Passphrases: A request to “confirm” one is a credential-harvesting attempt.
- Dice-roll sequences: These can reveal information used to reproduce wallet generation.
- Private keys and backup files: Do not upload them to a troubleshooting form or send them through chat.
A legitimate troubleshooting exchange can discuss a device model, a public error message, and the steps already attempted without requiring wallet secrets.
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Red flags that require a hard stop
- The message demands immediate action and prevents you from checking through an independently entered official address.
- The link opens a domain that resembles an official name but contains an extra term, altered spelling, or unfamiliar ending.
- The page asks for a seed phrase, passphrase, private key, dice-roll sequence, or backup file.
- The download page offers firmware without clearly identifying the exact model and release family.
- The supplied file has no matching entry in the official listing, or the filename is being used as the only compatibility test.
- The OpenPGP signature on
signatures.txtcannot be validated. - The SHA-256 value does not exactly match the value in the signed manifest.
- Someone instructs you to ignore a warning, use a different manifest, or install first and verify afterward.
When any of these occurs, disconnect from the suspicious page, do not install the file, and restart at an official address you enter yourself.
If you already clicked or downloaded something
You opened the link but entered nothing
Close the page, do not download its suggested files, and begin again from an official property. A click alone does not authenticate the page or make its instructions trustworthy.
You downloaded a firmware file but have not installed it
Do not open or transfer it to the device yet. Obtain the official file and signatures.txt through the independent route, then perform the signature and SHA-256 checks. If the file cannot be tied to the signed manifest, delete it and download again from the official listing.
You entered a wallet secret
Stop communicating with the sender. Because a disclosed seed, passphrase, private key, or backup may be compromised, use a trusted, independently obtained recovery plan appropriate to your wallet and security situation. Do not ask the same suspicious contact what to do next.
You installed an unverified file
Do not assume that a successful installation proves safety. Preserve the alert and file details, stop entering secrets, and contact support only through an official route that you navigate independently. Explain the exact model, file name, and steps taken without sending wallet secrets or backup material.
Keep the verification process current
Firmware listings, security notices, signing details, and upgrade instructions can change. The security-status page’s change log was updated October 1, 2026, so recheck the current status page, downloads page, and upgrade documentation when an alert arrives rather than relying on a cached page or an old article.
Version numbers are meaningful only in the context of the model and release family. Do not compare releases or choose an update until you know which COLDCARD you have and which official track applies to it.
Do these 3 things before closing this tab:
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- Pause; do not select the alert’s buttons or reply with information.
- Enter coldcard.com, coinkite.com, or the relevant official property manually or from a trusted bookmark.
- Check the complete address bar and locate any matching notice through the official site.
- If firmware is involved, identify your exact model and its official release family.
- Download the complete firmware file and
signatures.txtonly from the official route. - Verify the OpenPGP signature on
signatures.txt. - Calculate the firmware’s SHA-256 hash locally and compare it with the value in the signed manifest.
- Install only after every check passes, using the current documented upgrade procedure.
- Never provide seed words, passphrases, dice-roll sequences, private keys, or wallet backup files to purported support.
If a message, page, or file fails any check, it remains unverified. The safe response is to stop and re-enter the official route manually; the available official guidance cannot authenticate an unnamed alert or URL without examining its specific details.
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