# Bitcoin Hardware Krux

> Krux: DIY airgap signer running on Sipeed M5StickV / Maix Amigo.

Krux: DIY airgap signer running on Sipeed M5StickV / Maix Amigo.
Open-source, multi-language, stateless.
USE WHEN: integrating Krux, evaluating M5StickV-based signers.

- Page: https://ss33.ai/skills/claude-dev-suite/bitcoin-hardware-krux-17196417277
- Publisher: claude-dev-suite
- Category: [Finance & Markets](https://ss33.ai/skills/category/finance-and-markets-gri5ar) › [Payments & crypto](https://ss33.ai/skills/category/finance-and-markets-gri5ar/payments-and-crypto-jvjetm)
- License: MIT
- Source: https://github.com/claude-dev-suite/claude-dev-suite/blob/c32d3d81271b306861865a2397d594087cf0438b/skills/bitcoin/hardware/krux/SKILL.md

## Skill

SKILL.md: https://ss33.ai/api/v1/ss33/download/claude-dev-suite/bitcoin-hardware-krux-17196417277

# Krux

Bitcoin-only airgap signer for **Sipeed M5StickV** and **Maix Amigo**
hardware. Open-source firmware. Stateless: seed enters on use.

## Hardware

- Sipeed M5StickV (~$50).
- Maix Amigo (~$80, larger screen).
- Built-in camera + display.
- USB-C charging only (no data).

## Operation

1. Power on, boot Krux firmware from internal flash.
2. Enter seed via:
   - 24-word manual entry.
   - SeedQR scan.
   - Tinyseed (metal plate decoder).
3. Sign PSBTs via animated QR.

## Features

- Multi-language UI (English, Spanish, French, etc.).
- Multi-output signing (PSBT, message signing).
- BIP39 word entry helper.
- Tiny seed decoder for steel backup plates.

## Compatible wallets

- Sparrow.
- Specter.
- BlueWallet (limited).

## Use cases

- **Cheaper than SeedSigner DIY** if you don't have a Pi.
- **Educational** — explore HW signer internals.
- **Privacy-focused** — no permanent identity.

## Limitations

- **Smaller screen** (M5StickV).
- **Sipeed hardware availability** varies by region.
- **No SE** — same caveat as SeedSigner.

## See also

- [seedsigner/SKILL.md](../seedsigner/SKILL.md)
- [specter-diy/SKILL.md](../specter-diy/SKILL.md)
- [passport/SKILL.md](../passport/SKILL.md)