COLDCARD firmware

This commit fixes a bug in the COLDCARD hardware wallet's staged PSBT (Partially Signed Bitcoin Transaction) signing process. Previously, the wallet only re-checked the transaction hash if something was written to the lower 'input' staging region of its external memory. Writes to the upper 'output' staging region did not trigger a re-check, meaning a malicious or buggy process could potentially modify transaction data there without detection. The fix makes the write counter cover both regions, ensures oversized transaction files are rejected before staging, and updates the signing guard so that a write to the inactive region is treated as a new baseline rather than a false alarm. In short, it closes a gap where a transaction could be tampered with after user review but before signing.

This commit only changes automated test files for the COLDCARD hardware wallet firmware. It adds small delays, extra button presses, and adjusts test parameters to make the test suite run more reliably. There are no changes to the actual firmware code that runs on the device, so this cannot affect real users or introduce security vulnerabilities.

This commit fixes a bug in the COLDCARD password-notes feature. Previously, the 'Send Password' menu option was accidentally hidden when USB was disabled, because the code reused a setting meant for something else. The fix removes that wrong condition so the option always appears. This is a usability bugfix, not a security vulnerability: it restores intended access rather than opening an unintended one.

This commit fixes a simulator-only bug in the COLDCARD firmware's development/test tooling. A special code path that simulates the secure element's 'greenlight' LED signal was writing one byte to an internal pipe instead of the expected two bytes. That single-byte write shifted all later messages out of alignment, eventually causing the simulator to crash with a Python unpacking error. The fix changes that one write to two bytes and adds a regression test to catch similar mistakes. It does not affect real COLDCARD hardware or user funds.

This commit changes which physical buttons on the COLDCARD device are treated as 'done' or 'cancel' keys during a dice-roll seed-generation feature. It makes the choice depend on the device model (QWERTY keyboard vs. non-QWERTY) instead of hardcoding a mix of keys. The change is small and appears to be a UI/UX correctness fix rather than a security vulnerability. There is no clear evidence in the commit that this fixes an exploitable bug.

This commit adds a startup safety check for the hardware random-number generator (RNG) in the COLDCARD MK4 firmware. Before anything else can use randomness, the device now verifies that the rng_get() function actually reaches the hardware RNG and returns real entropy. If the check fails, the device deliberately halts ('bricks' itself) rather than boot. The change is defensive: it does not fix a known exploit, but it is designed to prevent a future bug or supply-chain issue where the firmware might accidentally use a non-hardware (and therefore weaker) source of randomness.

This update fixes a bug in the COLDCARD hardware wallet where a security mode called 'Delta Mode' could still access the Seed Vault through a feature called Seed XOR restore. Delta Mode is meant to restrict what an attacker or unauthorized user can do with the device. The fix blocks that access path. The bug was reported by someone named Rety.

This update fixes a bug in the COLDCARD hardware wallet's USB download command. Previously, a connected computer could ask the COLDCARD to read back almost anything it had temporarily stored in its extra memory chip (PSRAM), including uploaded transaction files or multisig setup files, even across different USB sessions and without encryption. Now the device only allows downloading the single most recent result it explicitly produced for the user (such as a signed transaction or backup), only over an encrypted session, and only until a new upload or session resets the permission.

This commit fixes a security bug where a malicious or compromised computer connected to a COLDCARD wallet could potentially swap the transaction data after the user reviewed it on the device screen but before the device signed it. The user might approve one transaction while the device signs a different one. The fix locks down the staged transaction data, re-checks it right before signing, and aborts with an error if anything changed.

This fix corrects a user-interface bug in COLDCARD's dice-roll seed-generation feature. Previously, if a user held down a digit key, the device treated the auto-repeating key events as multiple separate dice rolls, rapidly adding many unintended rolls. After the fix, a held key registers exactly one roll when released, matching how number entry already works elsewhere. This reduces the chance a user accidentally skews their random seed by holding a button too long.

This commit only removes an obsolete test from the test suite. The deleted test was for a duress PIN feature on the older Mk3 Coldcard and used a 'fetch' parameter that no longer exists. There is no change to firmware code that users run, so it cannot introduce a security vulnerability or fix one.

This commit only updates documentation. It clarifies that a BIP39 passphrase wallet backup stores an extended private key (XPRV) rather than the seed words or passphrase, and adds version numbers for older firmware behavior. There is no code change and no security fix or vulnerability introduced.

This commit only adds a single line to the changelog, describing a bugfix that was apparently already made elsewhere. The bug concerned how COLDCARD's 'View Seed Words' and backup features handled BIP-39 passphrase wallets when a passphrase was applied on top of a temporary seed. In that case, the device reportedly treated the master seed as the parent instead of the immediate temporary seed, potentially showing or backing up the wrong secret. Because the actual code change is not in this commit, we cannot directly verify the fix or assess its full security implications from this diff alone.

This commit changes how COLDCARD backup, clone, and Key Teleport features handle temporary seeds and BIP-39 passphrases. Previously, users could sometimes back up the main wallet even when a passphrase or temporary seed was active. Now the device always backs up the wallet currently in effect and warns the user first. This is a security-hardening change that reduces the risk of accidentally exposing or archiving the wrong secret, but it is not a fix for an active remote exploit.

This commit changes what the COLDCARD wallet displays on its 'View Seed Words' screen when a BIP-39 passphrase is active. Previously it showed the original 24 seed words plus a masked passphrase and the derived extended private key. Now it shows only the effective extended private key (and a note that a passphrase is in effect), hiding the underlying seed words. This is a deliberate UX/security hardening change, not a fix for an exploitable vulnerability.

This commit fixes a bug in the COLDCARD hardware wallet where, when the device is in 'Delta Mode' (a special temporary operating mode), opening the list of saved BIP-39 passphrases would reveal the passphrases and wallet fingerprints instead of securely wiping the seed first. The fix adds a call to wipe the seed if Delta Mode is active before displaying the saved passphrase menu. This prevents sensitive secret material from being exposed on screen in a mode meant to limit what an attacker can see.

This commit removes unused parameters from an internal function called fetch() in the COLDCARD firmware. There is no evidence this change fixes or introduces a security issue; it is purely a code cleanup that simplifies the function signature and removes dead code paths.

This commit only adds a thank-you credit to an upcoming release changelog. It does not change any code, so it cannot by itself fix or introduce a security issue. The actual BIP-322 validation bugfix must have been made in a different, earlier commit.

This update fixes how the COLDCARD hardware wallet's random-number generator (RNG) handles rare hardware faults. Previously, the device could silently continue using weak or repeated random numbers if the RNG reported a seed error. Now it detects those error flags, tries a safe recovery a few times, and if the problem persists it stops with an error instead of producing bad randomness. Two keyboard drivers were also updated so a temporary RNG failure does not lock the user out before login.

This commit fixes a buffer-validation bug in the COLDCARD Mk4 bootloader's secure callgate. The old code checked memory ranges using simple addition (address + length), which can overflow and trick the device into treating an attacker-controlled buffer as safe. The patch replaces those checks with subtraction-based math that cannot overflow, and also rejects negative input lengths. A security review by Karma-X is credited with the finding.

This update fixes a bug in the COLDCARD hardware wallet where signing a text message with the special 'Delta Mode' PIN would produce a signature that looked valid to anyone checking it. Delta Mode is a hidden feature that silently corrupts transaction signatures so attackers who force you to unlock your wallet cannot steal funds. The same protection was missing for message signatures, so an attacker could have tricked a victim into producing a seemingly valid signed message under duress. The fix makes message signatures produced in Delta Mode invalid, matching the existing behavior for transactions.

This commit changes how COLDCARD creates two special types of secrets: temporary seeds and the 'CCC' co-signing key. Previously these were generated purely from the device's own random number generator. Now the user must add their own randomness (for example by mashing buttons, rolling dice, or flipping coins) before the secret is created. This makes it harder for an attacker who has somehow compromised the device's random generator to predict or control those secrets. It is a defensive hardening change, not a fix for a known active attack.

This commit adds a warning screen before users create a Bitcoin wallet seed using only dice rolls. It tells users that no hardware randomness is added, and that the on-screen hash must be kept secret because anyone who sees it could recreate the wallet and steal funds. This is a user-experience and safety improvement, not a fix for a software vulnerability.

This commit adds build-time checks to ensure the firmware's random-number generator actually chains all the way down to the hardware chip. It does not fix a known exploit, but it prevents a future build misconfiguration from silently causing the wallet to use weaker random numbers, which could eventually make private keys guessable. Think of it as adding an assembly-line inspection that verifies a critical safety wire is connected end-to-end.

This commit changes how new COLDCARD wallets are created: instead of relying only on the device's internal random-number generators, users must now add their own physical randomness by either mashing keys, rolling dice, or flipping coins. The internal random sources are still used, but the user's extra randomness is mixed in. This is a security improvement meant to reduce the risk that a hidden flaw in the device's random-number hardware could produce a predictable wallet. The change also adds checks to catch obviously biased dice or coin results.