COINKITE Blog

COLDCARD 5.5.1 and 1.4.1Q

Thu, 02 Jul 2026 00:00:00 -1200

New COLDCARD Release: Versions 5.5.1 (Mk4/Mk5) and 1.4.1Q (Q)

Coinkite’s COLDCARD 5.5.1 and 1.4.1Q firmware release brings updated BIP-322 support for proof-of-reserves and message-signing PSBTs, improved WIF Store workflows for spending paper-wallet or WIF keys while keeping private keys air-gapped, and major Q-only upgrades to Secure Notes & Passwords, including groups, encrypted 7z backup/import, and optional use as a BIP-39 passphrase. It also includes a broad set of bugfixes & reliability improvements.

Shared Improvements - Both Mk and Q

BIP-322

BIP-322 has moved to Complete status, and the PSBT-based signing flow changed from earlier drafts. COLDCARD now follows the completed flow: Proof of Reserves and message-signing PSBTs must include PSBT_GLOBAL_GENERIC_SIGNED_MESSAGE, so the exact message shown to the user is part of the PSBT being signed. Messages must be non-empty and no longer than 330 characters. See the BIP-322 documentation for technical details.

We also improved how BIP-322 requests are shown on-screen. Simple message-signing requests are labeled BIP-322 Message, while proof-of-reserves requests are labeled Proof of Reserves and show the reserve amount before signing.

WIF Store

For anyone with funds sitting on WIF keys or paper wallets 🐋, COLDCARD now offers a cleaner way to spend them while keeping the private key air-gapped. WIF Store can export a watch-only descriptor for a WIF Store key, containing only public key material. Your WIF private key stays on COLDCARD and does not need to be imported into a desktop wallet (for example Bitcoin Core).

For Electrum, export the address from WIF Store and create a watching-only wallet using Import Bitcoin addresses or private keys. Since Electrum PSBTs from imported-address wallets do not include BIP-32 derivation paths, COLDCARD now detects the matching WIF Store key by address.

Learn more in the WIF Store docs, BIP-322 Proof of Reserves docs, and our earlier release post.

Q Only Improvements

Secure Notes & Passwords Improvements

Groups: Secure Notes & Passwords can now be organized into groups, making larger collections easier to browse and manage. Thanks to @Gen6G for the idea.

Standalone encrypted backup/import: Q can now export Secure Notes & Passwords as standalone encrypted 7z backups, using AES-256 in the same style as full COLDCARD backups. You can export the entire collection or just a single note/password, then restore it later with the same password-entry and decryption flow used for full COLDCARD backups.

Use as BIP-39 passphrase: Secure Note text or password text can now be applied as a BIP-39 passphrase when that fits your workflow and security model.

Shared Bugfixes

Keep NFC export tags alive for repeated probes, improving tap reliability, especially on iOS.
Reject witness-UTXO-only PSBT inputs when COLDCARD is expected to sign a non-SegWit input. When both UTXO fields are present, prefer non_witness_utxo for amount and script lookup. Thanks, @Damir.
Warn and skip fee calculation for legacy UTXOs with only witness UTXO data.
Disable Virtual Disk and NFC before activating HSM.
Fix P2PK signing. Both compressed and uncompressed P2PK spends are supported.
Fix incorrect default menu position for custom addresses.
Restore Delta Mode Trick PIN correctly from backup.
Show the proper error message for incorrect 7z headers.
Preserve an existing nickname when exiting nickname entry without changing it.
Fix incorrect error reporting in Verify/Decrypt Backup.
Fix incorrect error reporting for NFC Verify Address.
Treat a CCC key C challenge with a bad BIP-39 checksum as a wrong attempt instead of crashing the UX. It counts toward the three-strike lockout.
Reset CCC magnitude from CANCEL on empty input.
Fix a Yikes caused by OP_RETURN in CCC with whitelist enabled.
Fix TX Explorer crash on foreign input with non-standard sighash.
Fix crash from malformed JSON message-signing requests.
Reject UI-control bytes in JSON and QR text message-signing.
Show non-standard OP_RETURN outputs more accurately instead of hiding part of the script as “null-data”.
Prevent over-limit CCC address-whitelist imports from modifying policy after being rejected.
Fix a List Files case where deleting a file right after renaming it blanked the old name and left the renamed file.
Block reordered multi(...) multisig descriptors with the same keys as duplicates instead of reporting them as name-only changes.
Enforce WIF Store capacity when saving via QR WIF visualization.
Keep Seed XOR restore from the Temporary Seed menu temporary, even when the master seed is blank.
Fix binary signed-transaction (.txn) file sharing over NFC and QR.
Fix Yikes in transaction explorer when going to an output index in a transaction with only one output.
Fix Yikes from signmessage payloads encoded as BBQr.
Fix Yikes from CCC/SSSP NFC whitelist import.
Reject unrecognized payment addresses before wallet search during stricter address ownership validation.
Handle malformed NDEF records more robustly. Thanks, @Damir.
Ignore unexpected bkpw data if added to a backup. Thanks to @dmonakhov.
Fix 1-of-1 multisig signing.

Q-Only Bugfixes

Improve QR scanner recovery after setup failures, cancellations, timeouts, and delayed sleep commands. The scanner should be less likely to get stuck with the light left on.
Teleporting an unsigned multisig PSBT now sends the selected file instead of stale data.
Fix export message after teleport PSBT import and signing.
Fix BIP-21 QR amount rendering on the Payment Address screen. For example, amount=1.1 no longer displays as 1.00000001 BTC.
Fix Q seed-word entry cursor alignment for 12-word seeds.
Preserve visible seed words after failed QR scans.
Show clear errors for QR scan import failures, including wordlist-valid but checksum-invalid SeedQR data, instead of Yikes.
Fix Yikes when showing “QR too big” for a transaction output alone on an output-explorer page.
Fix Yikes when receiving a malformed full backup via Key Teleport.
Fix a keyboard debounce case where one key could remain stuck as pressed when another key was held.
Fix reversed visibility for the “Send Password” menu item inside Notes & Passwords.
Fix Yikes when using “Send Password” on an entry with no password field.
Do not show “Saving…” after a failed Notes & Passwords import.
Fix Notes & Passwords bulk import JSON with BBQr encoded as text.

Download the latest firmware

Get COLDCARD

Did you know? PushTx

After COLDCARD signs a transaction, PushTx can broadcast it with a simple NFC tap. Enable NFC Push TX, choose a public service or your own backend, then tap an NFC-enabled phone to your COLDCARD: the phone opens a browser link containing the freshly signed transaction and immediately pushes it to the Bitcoin network. COLDCARD stays offline, your private keys never leave the device, and the phone only handles the already-signed transaction. For stronger privacy, use your own PushTx service or activate a VPN on your phone. Learn more at PushTX.org.

Video Tutorials

We have a growing library of video tutorials on YouTube, and we’re still adding more.

Paper spam attempts

Wed, 24 Jun 2026 00:00:00 -1200

Remember letterhead? Now it’s the Newest Affinity Scam!

About Recent Physical Letters

We have received concerns from a few of our customers regarding a letter apparently from “Coinkite” asking them to upgrade their firmware for “Post QUanTUM” reasons.

This is a scam to steal your coins!

Coinkite would never send you a paper letter!

We delete all customer data, especially physical addresses, after 120 days.
Coinkite does not use CRM tools or any external third party tools.
Letters with branding of our wallet competitors have also been reported.
Our support tickets (and emails) also get deleted on a schedule.
We saw this in 2025, but this is a new round of letters in our brand style as well as our competitors.

We are actively investigating the situation. So far it seems most of the data is aggregated from multiple sources of leaks from other crypto providers and data filled-in from other data leaks over the years. Looks like someone is funding a spray-and-pray campaign over snail mail! We are so used to email spam it feels weird.

We recommend contacting support with more information so we can keep investigating. It’s very possible the customs and duties department of a country had a data leak. If it’s a large country, then that would expose all of our customers in that country. Recently we put together this rather long list of individual crypto company data breaches.

What Can I Do?

If you use Bitcoin to pay and shipped to a PO Box with an alias, then you have nothing to worry about! Most governments do not make that easy, and anon PO Box access is certainly not universal.

If you used a credit card, Stripe is the payment processor. They have not reported any breaches and we trust them (and the US laws they operate under) to report any they do have.

If you shipped DHL/Fedex, they will necessarily have your address, but we don’t know of any reports of breaches from them. We do not know what internal controls these carriers have, but we do know they have thousands of customer support representatives with access to address data.

The reality is we’re probably not the only company that knows you’re a Bitcoiner. Most people have bought Bitcoin-related products or services from other vendors over the years and shipped them to a home address, and any of those vendors and their third-parties are a possible source.

If you are certain that only Coinkite had a specific address and you receive this paper letter, please report it to support. We are hoping these letters are geographically targeted/limited, and that if we get enough reports, we can track which country or carrier leaked data.

What Are We Doing About It?

Remember to expect a “Your Data has been Blanked” email from Coinkite a few months after you interact with the store. If you have unclaimed giftcards, vouchers, or have an reseller relationship with us, then this does not happen. We may sometimes send a double email from time to time.
You can request accelerated data blanking anytime after your package arrives. Just email support and they can blank your profile and even remove your email.
We would like to shorten our data retention period, but credit card fraud makes that difficult.
All emails from our systems continue to be PGP signed.
We have audited our servers and found no reason to suspect any data breach.
If we identify a pattern in the reports, we will announce it.
We are adding another note to our disclaimer that is included in our transactional emails:

We are actively investigating this so please follow us for more updates: @Coinkite and @COLDCARDwallet

OPENDIME Turns 10: A Decade of Real, Physical Bitcoin

Mon, 01 Jun 2026 00:00:00 -1200

Well, it finally happened. Our little USB stick that could is officially a decade old this month. That’s right, OPENDIME is turning ten, and we’re as excited as you are that something we built to solve a problem has become such a staple in the Bitcoin space.

Buy OPENDIME

The Problem We Set Out to Solve

Back in 2016, the Bitcoin landscape was different. Most people were still keeping their coins on exchanges (yikes) or wrestling with complicated paper wallet setups. We saw a gap in the market for something that was both secure and dead simple to use. Something that worked like cash, you hand it to someone, and it’s theirs. No backsies.

So we created OPENDIME. A tiny, single-use Bitcoin bearer instrument that you could physically hand to someone. No accounts, no passwords, no recovery phrases to lose. Just Bitcoin in its purest form, a physical asset you can actually hold in your hand.

The Journey So Far

A lot has changed in ten years. We’ve seen bull runs, bear markets, fud, scams, and everything in between. Through it all, OPENDIME has kept doing exactly what it was designed to do: securely store Bitcoin and make it easy to pass from person to person.

We’ve gone through several iterations of the hardware, each one improving on the last while staying true to our original vision. The core concept hasn’t changed because it didn’t need to – sometimes you get it right the first time.

What You’ve Done With It

The most rewarding part of this journey has been seeing how you’ve used OPENDIME. We’ve seen everything from people using them to orange pill a friend, birthday presents, fashion accessories, elaborate art pieces, and so much more.

Join Us This Week

We’re celebrating this milestone at Coinkite this week, and we want you to be part of it. We’ll be sharing some cool uses of the OPENDIME, giveaways, and holding a rare 10% store-wide discount this week only!

Buy OPENDIME

It’s been a wild ride, and we’re just getting started. Here’s to another decade of making Bitcoin ownership simple and secure for everyone.

Check out more fun OPENDIME moments over the past decade:

Introducing the COLDCARD Mk5

Tue, 10 Mar 2026 00:00:00 -1200

The Mk4 is a proven workhorse. It’s secure, it’s air-gapped, and it gets the job done. But engineering is about moving forward. Today, we’re introducing the next step in that evolution: the COLDCARD Mk5.

The Mk5 builds on the trusted, battle-tested security core of the COLDCARD with a redesigned user experience focused on durability, visibility, and modern convenience.

Buy COLDCARD Mk5

What’s Evolved?

We’ve refined the parts you interact with most, making the entire process smoother and more robust.

Enhanced Interface: The Mk5 features a new 1.54-inch display protected by Gorilla Glass for maximum durability and significantly improved clarity. Complementing this is a completely redesigned keypad with precise, tactile keys for more reliable and confident entry.
Modern Design & Ergonomics: The entire unit has been re-engineered into a more compact and robust form factor. The USB-C port is now located on the bottom of the device, improving ergonomics and ease of access when the unit is powered on a desk.
Improved Wireless: NFC communication is faster and more reliable, enhancing the Push TX feature for seamless, air-gapped broadcasting of transactions to a compatible mobile device.
Personalization: For the first time, the COLDCARD will be available in multiple colors, allowing you to choose a style that suits you.

What’s Unchanged?

The core security principles that define a COLDCARD remain absolute. We don’t compromise on security.

100% Air-Gapped: Your keys never touch an internet-connected computer. This is a fundamental rule that will not change.
Dual Secure Element Key Storage: The master secret and 24-word seed phrase remain protected by two Secure Elements from different vendors.
Firmware Verification: The “Genuine” (green) or “Caution” (red) LED on boot-up still provides instant, verifiable proof of firmware integrity. The tamper-evident circuit is still visibly exposed.
Anti-Phishing Measures: The unique on-screen words for each PIN prefix remain a powerful defense against phishing, unique to each COLDCARD.
Open Source & Bitcoin-Only: The firmware remains open-source, audited, and designed exclusively for Bitcoin.

The Mk5 is 100% backwards-compatible with your existing COLDCARD backups and workflows. This is a seamless upgrade path for the community.

The Bottom Line

The COLDCARD Mk5 is the next generation of the hardware wallet you trust. It delivers meaningful improvements to usability and durability while standing firmly on the same uncompromised security foundation.

It’s available now.

Order Your Mk5 Now

Hands-On with the Mk5

Mk5 Image Gallery

BIP-322 Support, WIF Keys, and more!

Thu, 05 Mar 2026 00:00:00 -1200

New COLDCARD Feature Release: BIP-322 and WIF Support

Today we are releasing a new firmware version for COLDCARD. Tons of new features for both product families: Mk and Q!

New Features

BIP-322 Signing

COLDCARD can now sign BIP-322 “Proof of Reserve” PSBT files.

This requires a carefully crafted PSBT that does not represent a monetary transaction, but instead is demonstrating control over the keys for a list of UTXO, and also commits to a short text message. This BIP has been a long coming (assigned BIP number in 2018) but is truely a useful feature for proving you control UTXO and their keys in a comprehensive and secure way.

Read more about our implementation here. You will need a wallet or other tool to generate the specialzied PSBT needed to start.

See this X thread about how this might look!

WIF Store

This adds the ability to import foreign WIF keys (Wallet Import Format) and use them for PSBT signing. Import private keys that you have in WIF format (base58, starts with L or K) via SD Card, Virtual Disk, NFC, QR scanning or even—if you have the patience required—by directly entering all 50+ characters.

Once held in your “WIF Store”, any PSBT which calls for that key will be signed as needed. This process can be independant of your master seed (BIP-32 or BIP-39) wallet. Up to 30 keys can be held in the WIF store.

We can see this being useful for recovering paper wallets or cashing your OPENDIME, and perhaps some specialized emergencies. It will not be useful day to day.

Please be very careful when handling private keys!!

Export BIP-380 Extended Key Expression

Export BIP-380 extended key expressions.

Extended key expression are in the form [XFP/p/a/t/h]xpub and this is all you need to setup a multisig or single signer wallet. We support common address derivations and their implied address types, plus you can specify a custom path if needed.

Navigate to “Advanced/Tools -> Export Wallet -> Key Expression” and follow the prompts to get started.

Transaction Input Explorer

Shows data about the UTXOs being spent. Press (2) before approving a transaction to enter the new Transaction Explorer. You can page through the UTXO that the proposed transaction will be spending. This is similar to our existing output explorer which allows you to verify the destination details, but in this case you are checking the coin control of your wallet.

Smaller Features and Enhancements

Support for v3 transactions in PSBT files.
Option to type a derived BIP-85 secret as an emulated USB keyboard.
Nuke Device: purges all sensitive data and makes your COLDCARD e-waste.
CCC debug menu allows you to reset block height.
Show the BIP-39 passphrase on-screen (must scroll down) once new key is in effect.
New “Buried Settings” menu, inside Settings menu, for rarely-applied settings.
Add “Blue Wallet” option to “Export Wallet”
Detect duplicated inputs in PSBT file.
Bugfix: Replace / with - in exported file names of multisig wallet export artifacts.

Mk Specific Changes: 5.5.0 - 2065-03-05

Enhancement: Show QR of XOR-split seeds.

Q Specific Changes: 1.4.0Q - 2065-03-05

Bugfix: Empty notes in hobbled mode caused yikes upon menu entry.

Download the latest firmware

Get COLDCARD Mk or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

COLDCARD Bitcoin Spending Policy Released

Mon, 29 Sep 2025 00:00:00 -1200

New COLDCARD Feature Release: Spending Policies!

Spending Policy for Single Signers

You can now take your existing single-signer COLDCARD and reconfigure it so that the COLDCARD will refuse to sign transactions that are “too big” / “too fast”, or send to an address not on your whitelist.

We have even found a way to support 2FA authentication using the usual phone apps (RFC 6238). If that’s enabled, you will not be able to spend using your COLDCARD unless you also have your phone and provide the correct 6-digit numeric code.

You can combine any and all of these restrictions. They cannot be overriden with just the main PIN: To clear or disable this feature (once activated) requires a unique PIN code, called the Bypass PIN, followed by the normal Main PIN (and optionally, you can be asked to provide the first and last seed words). We have carefully blocked all access to the seed phrase, private keys, and other routes that might allow your master seed phrase to be revealed, which would otherwise allow a bypass of the policy.

See docs/spending-policy.md for more details about this new feature. Our docs website will be updated shortly to include this material as well.

“Enable HSM” and “User Management” menu items have moved into a new menu: Advanced > Spending Policy.
Old “CCC” feature has been renamed and moved into that menu as well: “Co-Sign Multisig”
Multisig Co-Signing (CCC) implements the same types of restrictions, but requires 2-of-3 (or higher) multisig wallet support and of course new UTXO.
There are two new trick-PIN types: the Bypass PIN itself, and also a fake version of that which silently clears your seed.
“Hobbled Mode” is our internal name for COLDCARD’s operation when spending policy is in effect: backups, settings changes, firmware updates and many other features are removed from the menu system.

Shared Improvements - Both Mk4 and Q

Added Bull Bitcoin export to Export Wallet menu.
Added warning for zero value outputs if not OP_RETURN.
Show QR codes of output addresses in transaction output explorer. Explorer is now offered for transactions of all sizes, not just complex ones.
Added file rename, when listing contents of SD card.
Added ability to restore Coldcard backup via USB (needs latest of ckcc version).
Address ownership allows to specify particular multisig wallet in which to search, if wallet query parameter is provided via trivial extension to BIP-21. Example: tb1q4d67p7stxml3kdudrgkg5mgaxsrgzcqzjrrj4gg62nxtvnsnvqjsxjkej0?wallet=Haystack

Bugfixes

If all change outputs have nValue=0, they were not shown in UX.
Disallow negative input/output amounts in PSBT.
Fix filesystem initialization after Wipe LFS or Destroy Seed.
NFC loop exporting secrets would not work after first value exported.
Multisig address format handling.
Ownership check failing to find addresses near max (~760), needed to be re-run to succeed

5.4.4 - 2025-09-26 – Mk4 Specific Changes

Bugfix: Part of extended keys (xpubs) were not always visible.
Change: Mk4 default menu wrap-around lowered from 16 to 10 items.

1.3.4Q - 2025-09-26 – Q Specific Changes

Enhancement: Enters “forever calculator” mode when Q would otherwise be electronic waste (i.e. after 13 PIN failures). Always enabled, regardless of “login calculator” setting.
Bugfix: Correct line positioning when 24 seed words displayed.

Download the latest firmware

Get COLDCARD Mk4 or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

Earn Sats Straight to Cold Storage with Zaprite and COLDCARD

Tue, 09 Sep 2025 00:00:00 -1200

Earn Sats Straight to Cold Storage with Zaprite and COLDCARD

Zaprite and COLDCARD: Empowering Bitcoin Payments with Cold Storage Security

Bitcoin adoption continues to grow among freelancers, creators, and businesses worldwide. Yet one challenge persists – many users receive payments into hot wallets or custodial services, leaving funds vulnerable to hacks, freezes, or third-party surveillance. A new integration between Zaprite and COLDCARD addresses this gap by pairing seamless Bitcoin payments with unmatched hardware security.

A Perfect Match: Payments and Cold Storage

Zaprite is a Bitcoin-native payments and invoicing platform that enables individuals and businesses to accept Bitcoin directly, without intermediaries. Users can generate invoices, create payment links, and manage both recurring and one-off payments while maintaining full control of their private keys.

COLDCARD, created by Coinkite, is a Bitcoin-only hardware wallet trusted for its air-gapped security model. It ensures private keys never touch an internet-connected device, safeguarding them with dual secure elements, verifiable source code, and Bitcoin-only firmware.

Together, Zaprite and COLDCARD offer a smooth path from receiving Bitcoin to securing it in cold storage.

How the Integration Works

With the new integration, Zaprite users can receive Bitcoin payments directly to addresses generated by their COLDCARD wallet. Funds land instantly, free from custodians or vendor lock-in. Once received, users can move their Bitcoin into long-term storage using COLDCARD’s PSBT workflows – via NFC, MicroSD, or QR codes.

This workflow provides two critical benefits:

Convenience – Users gain the ability to invoice and accept Bitcoin seamlessly through Zaprite.
Sovereignty – Funds remain under the user’s control, secured by COLDCARD’s battle-tested hardware design.

Voices from the Teams

“Interoperability and open standards are essential for Bitcoin adoption,” said NVK, Co-Founder of Coinkite. “This collaboration ensures that users can move from payment to cold storage with minimal friction.”

John Magill, Founder & CEO of Zaprite, echoed this vision: “By integrating COLDCARD, our users get Zaprite’s seamless payment experience paired with the security of self-custody. It’s the perfect blend of convenience and sovereignty.”

Why This Matters

Bitcoin thrives on openness and trustlessness. This integration reflects that ethos by allowing users to accept payments in a non-custodial way and secure them without relying on third parties. It represents a step toward a world where freelancers, entrepreneurs, and businesses can operate fully in Bitcoin – from payments to long-term storage – while keeping ownership of their wealth.

As adoption accelerates, collaborations like this will continue to push Bitcoin forward, reinforcing its role as sound money for the digital age.

Learn more about the Zaprite integration

Get COLDCARD Mk4 or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

Coldcard Cosign and Key Teleport

Thu, 17 Apr 2025 00:00:00 -1200

New COLDCARD Release: Many BIG features & Fixes!

Two New Heavyweight Features

CCC: COLDCARD can now Co-sign like collaborative multisig HSMs, no centralized servers needed.

KeyTeleport: Send secrets on a video call to other COLDCARD! Securely move seeds, secure notes/passwords, multisig PSBTs, even full backups (full clone), between two Q using QR or NFC

CCC - ColdCard Cosign

COLDCARD holds a key in a 2-of-3 multisig, in addition to the normal signing key it has.

It applies a spending policy like an HSM:
- velocity and magnitude limits
- whitelisted destination addresses
- 2FA authentication using phone app (RFC 6238)
But will sign its part of a transaction automatically if those condition are met, giving you 2 keys of the multisig and control over the funds
Spending policy can be exceeded with help of the other co-signer (3rd key), when needed
Cannot view or change the CCC spending policy once set, policy violations are not explained
Existing multisig wallets can be used by importing the spending-policy-controlled key
CCC Demo Video (youtube) and Online docs (coldcard.com)

Key Teleport (Q)

Easily and securely move seed phrases, secure notes/passwords, multisig PSBT files, and even full Coldcard backups, between two COLDCARD Q using QR codes and/or NFC with helper website.

Can send master seed (words, xprv), anything held in seed vault, secure notes/passwords (singular, or all) and PSBT involved in a multisig to the other co-signers
Full COLDCARD backup is possible as well, but receiver must be “unseeded” Q for best result.
In other words, you can clone your Q over a zoom call to another person.
ECDH to create session key for AES-256-CTR, with another layer of AES-256-CTR using a short password (stretched by PBKDF2-SHA512) inside
Receiver shows sender a (simple) QR and a numeric code; sender replies with larger BBQr and 8-char password
See protocol spec in docs/key-teleport.md
Online docs are coming soon.
Related website is: keyteleport.com

Teleport of Multisig PSBT

After you sign a multisig PSBT, you have option to “Key Teleport” the PSBT file to any one of the other signers in the wallet. We already have a shared pubkey with them, so the process is simple and does not require any action on their part in advance. Plus, starting in this firmware release, COLDCARD can finalize multisig transactions, so the last signer can publish the signed transaction via PushTX (NFC tap) to get it on the blockchain directly.

Above is an example of the menu shown where you select who should get the PSBT file next. As you can see two have already signed the file (checkmarks).

Shared Improvements - Both Mk4 and Q

New Feature: Multisig transactions are finalized when sufficiently signed. Allows use of PushTX with multisig wallets.
New Feature: Signing artifacts re-export to various media. Now you have the option of exporting the signing products (transaction/PSBT) to different media than the original source. Incoming PSBT over QR can be signed and saved to SD card if desired.
New Feature: Multisig export files are signed now. Read more here
Enhancement: NFC export usability upgrade: NFC keeps exporting until CANCEL/X is pressed
Enhancement: Add Bitcoin Safe option to Export Wallet
Enhancement: 10% performance improvement in USB upload speed for large files
(Q only) Enhancement: Always choose the biggest possible display size for QR

Bugfixes

Do not allow change Main PIN to same value already used as Trick PIN, even if Trick PIN is hidden.
Fix stuck progress bar under Receiving... after a USB communications failure
Showing derivation path in Address Explorer for root key (m) showed double slash (//)
Can restore developer backup with custom password other than 12 words format
Virtual Disk auto mode ignores already signed PSBTs (with “-signed” in file name)
Virtual Disk auto mode stuck on “Reading…” screen sometimes
Finalization of foreign inputs from partial signatures. Thanks Christian Uebber!
Temporary seed from COLDCARD backup failed to load stored multisig wallets
Destroy Seed also removes all Trick PINs from SE2.
Lock Down Seed requires pressing confirm key (4) to execute
(Q only) Only BBQr is allowed to export Coldcard, Core, and pretty descriptor

Follow-up Release

Recently, we’ve released an update which builds on above and fixes a number of minor issues:

Enhancement: Text word-wrap done more carefully so never cuts off any text, and yet doesn’t waste space.
Bugfix: Add current tmp option, which could be shown in Seed Vault menu under specific circumstances, would corrupt master settings if selected.
Bugfix: PUSHDATA2 in bitcoin script caused yikes.
Bugfix: Warning for unknown scripts was not shown at the top of the signing story.

5.4.3 - 2025-05-14 – Mk4 Specific Changes

Bugfix: With both NFC & Virtual Disk OFF, user cannot exit Export Wallet menu. Gets stuck in export loop and needs reboot to escape.
Bugfix: Part of extended keys in stories were not always visible.

1.3.3Q - 2025-05-14 – Q Specific Changes

Bugfix: Do not allow to teleport PSBTs from SD card when CC has no secrets.
Bugfix: Calculator login mode: added “rand()” command, removed support for variables/assignments.

Download the latest firmware

Get COLDCARD Mk4 or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

New COLDCARD EDGE Version Released

Wed, 19 Feb 2025 00:00:00 -1200

New COLDCARD EDGE Release: Versions 6.3.5X (Mk4) and 6.3.5QX (Q).

Catch-Up Release

This release is meant to catch-up Edge with the recent main release which included many useful bugfixes and improvements. Read about it in our most recent Feb 13/25 post.

One important non-code change is we’ve reconsidered the startup warning we used to show, and it now reads:

This firmware version is qualified for use with wallets (such as AnchorWatch) that keep redundant key schemas for recovery independent of COLDCARD. We support the very latest Bitcoin innovations in the Edge Version.

This means we think this “The Edge” is a little less sharp now, but please still keep backups and use key schemes which allow full recovery for single failed signer. Multisig with 2-of-2 or 57-of-57 keys are still bad ideas!

Learn more about Miniscript and/or Taproot support in these wallets which support COLDCARD:

We offer no third-party software warranties, please do your own research.

What is EDGE?

Branch new_edge is our long-lived branch that contains features that may not be ready for prime time, such as Taproot and Tapscript, BSMS and Miniscript.

Our standards for releasing new Edge versions are lower, so we can iterate faster and get these advancements out to other developers as soon as possible.

Edge releases typically contain all the latest Mk4/Q features from our most recent mainstream firmware.

Shared Changes - Both Mk4 and Q

Allow origin-less extended keys in multisig & miniscript descriptors
Static internal keys disallowed - all keys need to be ranged extended keys

Download the latest firmware

Get COLDCARD Mk4 or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

New Release: Signing and Address Display

Thu, 13 Feb 2025 00:00:00 -1200

New COLDCARD Release: Versions 5.4.1 (Mk4) and 1.3.1 (Q)

New (Message) Signing Features

We love message signing (and transaction signing too). It’s useful to prove ownership of UTXO and to test access to appropriate private keys. We’ve added some new ways to sign messages:

Sign message from secure note text, or password note.
Sign message with key resulting from positive ownership check. Press (0) and enter or scan message text to be signed.
Sign message with key selected from Address Explorer Custom Path menu. Press (2) and enter or scan message text to be signed.
JSON message signing. Use JSON object to pass data to sign:

    { "msg":"required: text to sign",
      "subpath":"optional: m/84h/99h/4/2",
      "addr_fmt": "optional" }

Delta Mode Enhancements

“Delta Mode” is a special Trick PIN mode where we let seem to let the attackers into your vault. They see the true XPUB and your actual UTXO. Signing even seems to work, but if the transaction is broadcast, it will not be accepted by the network. We’ve added some updates to handle more cases where the “jig is up” and the COLDCARD wipes the seed rather than reveal your seed words or other secrets.

Hide Secure Notes & Passwords in Deltamode. Wipe seed if notes menu accessed.
Hide Seed Vault in Deltamode. Wipe seed if Seed Vault menu accessed.
Catch more DeltaMode cases in XOR submenus. Thanks @dmonakhov

Address Display Changes

New address display format improves address verification on screen by splitting addresses into groups of 4 and showing with a space between them. Here’s what that looks like:

Related: Added option to show/export full multisg addresses without censorship. Enable in Settings > Multisig Wallets > Full Address View.

Other Changes

Both Mk4 and Q

Enhancement: Add ability to switch between BIP-32 xpub, and obsolete SLIP-132 format in Export XPUB
Enhancement: Use the fact that master seed cannot be used as ephemeral seed, to show message about successful master seed verification.
Enhancement: Allow devs to override backup password.
Enhancement: If derivation path is omitted during message signing, derivation path default is no longer root (m), instead it is based on requested address format (m/44h/0h/0h/0/0 for p2pkh, and m/84h/0h/0h/0/0 for p2wpkh). Conversely, if address format is not provided but subpath derivation starts with: m/84h/... or m/49h/..., then p2wpkh or p2sh-p2wpkh respectively, is used.
Bugfix: Sometimes see a struck screen after Verifying… in boot up sequence. On Q, result is blank screen, on Mk4, result is three-dots screen.
Bugfix: Do not allow to enable/disable Seed Vault feature when in temporary seed mode.
Bugfix: Bless Firmware causes hanging progress bar.
Bugfix: Prevent yikes in ownership search.
Bugfix: Factory-disabled NFC was not recognized correctly.
Bugfix: Be more robust about flash filesystem holding the settings.
Bugfix: Do not include sighash in PSBT input data, if sighash value is SIGHASH_ALL.
Bugfix: Allow import of multisig descriptor with root (m) keys in it. Thanks @turkycat
Change: Do not purge settings of current active tmp seed when deleting it from Seed Vault.
Change: Rename Testnet3 -> Testnet4 (all parameters unchanged).

Mk4 Specific Changes

5.4.1 - 2024-02-13

Enhancement: Export single sig descriptor with simple QR.

Q Specific Changes

1.3.1Q - 2024-02-13

New Feature: Verify Signed RFC messages via BBQr
New Feature: Sign message from QR scan (format has to be JSON)
Enhancement: Sign/Verify Address in Sparrow via QR
Enhancement: Sign scanned Simple Text by pressing (0). Next screen query information about which key to use.
Enhancement: Add option to “Sort By Title” in Secure Notes and Passwords. Thanks to @MTRitchey for suggestion.
Bugfix: Properly re-draw status bar after Restore Master on COLDCARD without master seed.

Download the latest firmware

Get COLDCARD Mk4 or Q

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!

COINKITE Blog

COLDCARD 5.5.1 and 1.4.1Q

New COLDCARD Release: Versions 5.5.1 (Mk4/Mk5) and 1.4.1Q (Q)

Shared Improvements - Both Mk and Q

BIP-322

WIF Store

Q Only Improvements

Secure Notes & Passwords Improvements

Shared Bugfixes

Q-Only Bugfixes

Further reading

Did you know? PushTx

Video Tutorials

Paper spam attempts

About Recent Physical Letters

What Can I Do?

What Are We Doing About It?

OPENDIME Turns 10: A Decade of Real, Physical Bitcoin

The Problem We Set Out to Solve

The Journey So Far

What You’ve Done With It

Join Us This Week

Introducing the COLDCARD Mk5

Hands-On with the Mk5

Mk5 Image Gallery

BIP-322 Support, WIF Keys, and more!

New COLDCARD Feature Release: BIP-322 and WIF Support

New Features

BIP-322 Signing

WIF Store

Export BIP-380 Extended Key Expression

Transaction Input Explorer

Smaller Features and Enhancements

Mk Specific Changes: 5.5.0 - 2065-03-05

Q Specific Changes: 1.4.0Q - 2065-03-05

Video Tutorials

COLDCARD Bitcoin Spending Policy Released

New COLDCARD Feature Release: Spending Policies!

Spending Policy for Single Signers

Related Changes

Shared Improvements - Both Mk4 and Q

Bugfixes

5.4.4 - 2025-09-26 – Mk4 Specific Changes

1.3.4Q - 2025-09-26 – Q Specific Changes

Video Tutorials

Earn Sats Straight to Cold Storage with Zaprite and COLDCARD

Earn Sats Straight to Cold Storage with Zaprite and COLDCARD

Zaprite and COLDCARD: Empowering Bitcoin Payments with Cold Storage Security

A Perfect Match: Payments and Cold Storage

How the Integration Works

Voices from the Teams

Why This Matters

Video Tutorials

Coldcard Cosign and Key Teleport

New COLDCARD Release: Many BIG features & Fixes!

Two New Heavyweight Features

CCC - ColdCard Cosign

Key Teleport (Q)

Teleport of Multisig PSBT

Shared Improvements - Both Mk4 and Q

Bugfixes

Follow-up Release

5.4.3 - 2025-05-14 – Mk4 Specific Changes

1.3.3Q - 2025-05-14 – Q Specific Changes

Video Tutorials

New COLDCARD EDGE Version Released

New COLDCARD EDGE Release: Versions 6.3.5X (Mk4) and 6.3.5QX (Q).

Catch-Up Release

What is EDGE?

Shared Changes - Both Mk4 and Q

Video Tutorials

New Release: Signing and Address Display

New COLDCARD Release: Versions 5.4.1 (Mk4) and 1.3.1 (Q)

New (Message) Signing Features

Delta Mode Enhancements

Address Display Changes

Other Changes

Both Mk4 and Q

Mk4 Specific Changes

5.4.1 - 2024-02-13