Bitcoin HWI to Stop Adding Hardware Devices as Replacement Remains Unfinished

Bitcoin hardware-wallet bridge enters its final phase

Bitcoin HWI will stop accepting support for new hardware devices and features after its remaining MuSig2 work is finished. HWI is an interface that connects Bitcoin wallet software with hardware wallets, which are devices used to approve and sign transactions.

The maintainer expects to issue what will probably be HWI’s final release after completing that work. The project would then receive minimal maintenance until a suitable replacement is available.

Main details of the transition

• HWI has effectively operated in maintenance mode for years and has largely been maintained by one person.
• No retirement date has been announced, and the project has not been archived.
• Existing supported devices are not confirmed to be losing access.
• The notice does not indicate that users’ bitcoin is at risk.
• BHWI, a possible replacement written in Rust, has published parity tests for four device families.
• No production wallet deployment of BHWI was named in the supplied report.

What the HWI maintainer announced

The HWI maintainer said on Aug. 18 that the project would no longer accept new devices or features beyond the remaining MuSig2 work. After a likely final release, maintenance is expected to be limited while developers wait for a replacement that can take HWI’s place without requiring major interface changes.

HWI supports common hardware-wallet tasks through one interface. These include finding a connected device, retrieving public keys, showing a receiving address and sending a partially signed Bitcoin transaction to a device for approval.

The report names Ledger, Trezor, Coldcard, BitBox and Jade as examples of devices that can use this bridge.

BHWI aims to preserve HWI compatibility

BHWI is the replacement candidate cited by the maintainer. It uses Rust and aims to keep command output compatible with HWI.

According to the report, the maintainer said HWI’s use of Python prevents deterministic builds, which are designed to produce reproducible release files. This has kept HWI from being distributed with Bitcoin Core.

BHWI may address that packaging problem, but compatible commands alone do not complete the transition. Wallet teams must still package the new software, test their supported devices and confirm that their transaction workflows continue to work.

Wallet developers still face integration work

Bitcoin Core uses a separate external-signer system, with HWI documented as an example. That design means another compatible program can replace HWI in principle.

Other wallet projects use or distribute HWI in different ways. The supplied report says Specter Desktop pins HWI version 3.1.0 in its dependency file, while Wasabi Wallet’s documentation connects its hardware-wallet support to HWI.

These projects may need to retest device discovery, address display and transaction signing. Developers must also decide who will handle changes involving device firmware, operating systems and vendor protocols.

No firm retirement or migration date

HWI remains active under minimal maintenance, and there is no announced date for its retirement. BHWI has not yet demonstrated a named production handoff in the supplied material.

The immediate issue is therefore not a confirmed failure of existing hardware wallets. It is the risk that wallet software may struggle to support future devices or features if migration work is delayed.

Source

• CryptoSlate