COLDCARD firmware

This change makes the COLDCARD hardware wallet display the user's BIP-39 passphrase on the device's own screen after it is applied. This is a deliberate UX change, not a hidden bug. It could slightly increase the risk that someone physically near the device (or a camera) sees the passphrase, but it only appears after the user has already entered it and only on the local screen. The commit does not introduce a remote or software vulnerability.

This commit adds a new user-facing 'Nuke Device' feature to the COLDCARD hardware wallet. It lets the owner deliberately wipe the seed and permanently brick the secure element, rendering the device unusable. The change also removes some unreachable cleanup code from the existing seed-clearing routine. There is no evidence in the commit of a hidden or malicious trigger; it appears to be an intentional, user-initiated self-destruct function.

This small change lets users cancel out of a 'go to index' prompt in the COLDCARD's transaction explorer instead of being forced to enter a number. It is a minor user-experience fix with no direct security impact visible from the code change.

This commit adds a small user-interface convenience to the COLDCARD transaction explorer: users can now press the '2' key to jump directly to a specific input or output index, instead of paging through items one screen at a time. It also fixes a minor edge case where pressing the left/back key from the first page could produce a negative starting index. There is no security-relevant change here.

This commit adds a new on-device 'Transaction Input Explorer' feature for the COLDCARD hardware wallet. It lets users inspect the inputs (UTXOs) being spent before approving a transaction, alongside the existing output explorer. The change is primarily a user-interface enhancement and does not appear to fix a security vulnerability. It also includes related display improvements and test coverage.

This commit adds a new convenience feature: after deriving a secret using the BIP-85 standard, the COLDCARD can now type that secret out as USB keyboard keystrokes for all supported secret types (seed words, xprv, WIF, hex, password). Previously this USB typing was only available for password-type secrets. The change also cleans up how the on-screen prompt offers the '(6)' keystroke option. There is no direct evidence in the commit that this fixes a security bug; it appears to be a user-experience feature addition.

This commit adds a small user-interface convenience: after splitting a secret backup phrase into XOR parts on a COLDCARD hardware wallet, users can now view those parts as QR codes by pressing the '4' key (in addition to the existing QR key on Q models). It is a feature enhancement, not a security fix or vulnerability.

This is a bugfix for the COLDCARD's 'SSSP' (a spending-policy/velocity-limit feature). Previously, when a user was operating with a temporary seed, the device could not update the stored 'last signed block height' after signing a transaction. That meant a temporary-seed session could not advance the anti-rollback counter, so later signing attempts could be wrongly rejected as 'rewound' or could, in some configurations, leave the velocity-limit tracking stale. The fix lets the block-height update be saved to the shared settings area even when the current active key is a temporary seed, rather than requiring the master seed's settings area.

This change fixes how COLDCARD figures out the address format for multisig transactions. Previously it guessed based on the derivation path numbers in the PSBT's XPUB records, which can be misleading or attacker-controlled. Now it looks directly at the actual witness/redeem script in the transaction input, which is harder to fake. A wrong address format could make the wallet think it is signing one type of address while the transaction really pays to another, potentially tricking the user into approving a payment they did not intend.

This commit fixes a bug in COLDCARD's 'deltamode' duress feature. Delta mode is meant to let a thief who knows a slightly wrong PIN sign transactions with corrupted signatures that look valid but don't actually protect any bitcoin. The bug was that the fake signature was produced from a fixed, predictable placeholder instead of from the real transaction data. A security research team claims this predictability could let an attacker who captures two such signatures recover the wallet's private keys, potentially stealing all funds. The patch makes the corrupted signature depend on the real transaction hash, removing that mathematical shortcut.

This is a small bug fix in the COLDCARD hardware wallet's 'trick PIN' feature. Trick PINs let users set up special PINs that do things like wipe the device or unlock specific spending policies. The fix makes the device refresh its trick-PIN list before looking for a PIN that unlocks a spending policy. Without the refresh, the device might fail to find a newly added or changed unlock-policy PIN, which could leave a legitimate user unexpectedly unable to access funds or use a protective feature as intended. There is no direct evidence in the commit that this is exploitable by an attacker.

This change fixes a potential bug in how COLDCARD's 'trick PIN' feature removes special unlock PINs. Before deleting those PINs, the code now reloads the trick PIN data from storage. Without the reload, the function might operate on stale in-memory data and fail to delete some trick PINs that should have been removed. That could leave behind an unintended bypass PIN after a feature is turned off, which is a security-relevant state.

This update prevents a COLDCARD hardware wallet from accepting an empty BIP-39 passphrase when the command comes over the USB connection. A BIP-39 passphrase is an extra word or phrase users can add to their seed to create a separate wallet. Previously, an empty passphrase could be sent through USB, which might let software on the connected computer silently access the user's default/no-passphrase wallet without the user typing anything on the device. Now the device rejects empty passphrases over USB, so the user must intentionally enter a passphrase on the device itself.

This commit fixes a user-interface bug on the COLDCARD MK4 that occurred when restoring a wallet backup over USB. After a USB restore, the device was supposed to let the user enter the backup password as a series of seed words, but the on-screen word-entry menu did not work correctly because the device was not coming from the normal menu flow. The fix detects the USB case and uses a simpler, direct word-entry path instead. There is no direct evidence this is a security vulnerability; it appears to be a usability/functional bug fix.

This commit fixes a security policy bug in the COLDCARD hardware wallet. In 'hobbled mode'—a restricted operating mode meant to limit what secrets can leave or be combined—the device was incorrectly allowing users to include the wallet's master seed as one of the parts when restoring a seed via XOR. The patch removes that option when hobbled, so a locked-down COLDCARD can no longer be tricked or misused into mixing its master seed into an externally reconstructed secret.

This update changes what happens on the COLDCARD Q hardware wallet after someone enters the wrong PIN 13 times and the device becomes permanently locked ("bricked"). Instead of showing only a useless "I Am Brick!" screen, the Q model now turns into a simple calculator. The change also lets the calculator's login prompt check whether PIN attempts remain before trying to log in, and adds simulator options so developers can test bricked devices. There is no direct evidence in the commit that this fixes an active security vulnerability; it reads as a usability enhancement for a device that is already considered lost.

This commit reorganizes how a COLDCARD device decides it is 'bricked' and what it does next. It moves the brick check from the main boot code into the PIN-handling code, and slightly cleans up a calculator/login helper. The change appears intended to make bricked devices stop earlier in boot and still offer a calculator-only recovery screen on QWERTY models. There is no clear vulnerability being fixed; it reads more like a defensive hardening or refactor.

This commit changes what a COLDCARD Q device does when its secure element (SE) is 'bricked'—a state where the hardware security chip is no longer usable. Previously, the device immediately entered DFU (device firmware update) mode and stopped. After this change, the device first opens a calculator-like text interface that can run forever, and only then enters DFU mode. The commit title 'Q: brick into forever calculator' suggests this is intentional behavior for bricked devices, not a vulnerability. The change also removes the ability to enter a PIN from within that calculator when reached through this bricked path, so it does not appear to provide a way to bypass authentication.

This commit adds a new menu option called 'Restore Seed XOR' to the Temporary Seed menu on a COLDCARD device. It simply exposes an existing feature (restoring a seed from XOR-encoded parts) in a new place where users can reach it more easily. There is no code change to how seeds are stored, processed, or protected.

This update fixes a user-interface crash in the COLDCARD hardware wallet when it tries to display very large QR codes. Before the change, certain long transaction outputs (for example, OP_RETURN data or unusual scripts) could make the on-device QR generator fail and throw an error, interrupting transaction review. The patch catches that failure, shows a 'QR too big' placeholder instead, and lets the user keep reviewing the transaction. It is a denial-of-service-style reliability fix rather than a theft-of-funds vulnerability.

This commit adds a new USB command that lets a connected computer restore a COLDCARD wallet backup onto the device. The user must confirm on the device screen, and the backup file's checksum is verified. However, because restoring a backup replaces the wallet seed, the feature is security-sensitive. The commit also blocks this command in HSM (unattended signing) mode, which is a good protective measure. There is no direct evidence of a vulnerability in the patch, but the feature increases the attack surface available over USB.

This commit only adds automated tests for an existing firmware feature called 'deltamode' trick PINs. It does not change the actual COLDCARD firmware code that users run. The tests confirm that when a deltamode trick PIN is active, the device produces an intentionally invalid Bitcoin signature and does not wipe the seed. No security bug is introduced or fixed here.

This commit contains only trivial non-code changes: a comment rewording, a stylistic Python list change with identical behavior, a typo fix in a user-facing message, and a hyphenation fix in a test file docstring. There is no security-relevant change.

This commit only updates user documentation. It fixes a typo in a menu path and adds a new section explaining what to do if a user forgets their 'Bypass PIN' for the Spending Policy feature: perform a factory reset via 'Destroy Seed' and restore from backup. There is no code change and no security vulnerability is being fixed.

A developer added a comment in the COLDCARD MK4 bootloader code flagging that a function reads a configuration byte from a secure chip but does not check whether the read operation failed. If the read fails, the function could return an uninitialized or garbage value. This is a code-quality and potential security issue, but the patch only adds a comment—it does not fix the bug.