COLDCARD firmware

This commit fixes a small user-interface bug in the COLDCARD hardware wallet. Previously, after signing a transaction that was not yet finalized, the device still offered a menu option to display a QR code of the transaction ID (TXID). Because the transaction ID can only be reliably computed once the transaction is finalized, offering the QR code earlier could mislead the user or show invalid/incomplete data. The fix hides that QR-code option unless the transaction is finalized. There is no direct evidence of funds being stolen or a remote attack.

This commit only changes user-facing text labels in the COLDCARD firmware. It expands the abbreviation 'MSG' to 'Message' on screens that have enough space, and updates the corresponding automated tests to match the new wording. There is no change to security logic, cryptography, or how data is handled.

This commit adds a new user-facing verification step for BIP-322 'Proof of Reserves' messages on the COLDCARD hardware wallet. Before signing a proof-of-reserves transaction, the device now asks the user to import or type the original human-readable message, checks that it matches the cryptographic hash embedded in the transaction, and shows it on screen for approval. This is a security-hardening feature: it closes a gap where the user might otherwise sign a proof without seeing what message they are actually attesting to. The commit itself is defensive and does not appear to introduce an obvious vulnerability, but it is a partial implementation (marked with TODOs) and the change is large enough that bugs in the new input paths could affect signing safety.

This commit makes a small user-interface change in the COLDCARD firmware for BIP-322 proof-of-reserves signing. When the user chooses to type in the human-readable message manually, pressing Cancel on the empty text-entry screen now returns to the signing flow instead of aborting the entire operation. The change is accompanied by new tests that verify the device rejects empty or wrong messages with clear failure screens. There is no direct evidence in the commit that this fixes an exploitable security vulnerability; it appears to be a usability improvement to prevent accidental cancellation.

This commit adds support for BIP-322 Proof of Reserves signing on COLDCARD hardware wallets. It lets users prove they control certain Bitcoin addresses by signing a special non-spending transaction, without actually moving funds. The change also allows transaction version 0 only for these proof-of-reserve transactions, and blocks it for normal payments to prevent potential misuse.

This commit only adds a single line to a test file. It checks that when a user adds a BIP-39 passphrase to create a temporary seed, the COLDCARD device displays the passphrase back to the user on screen. This is a test-only change and does not modify the firmware itself. It is not a security fix or vulnerability.

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 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 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 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.