Direct comparison
Bitcoin-only with USB app vs. air-gapped PSBT — BitBox02 open source without air-gap, Coldcard Mk4 offline-first.
Key differences to help you choose, without an overall score.
| criterion |  BitBox02 Bitcoin-only |  Coldcard Mk4 |
|---|---|---|
| Connectivity | USB | USB · NFC |
| Platforms | Windows · macOS · Linux · Android | Windows · macOS · Linux · iOS · Android |
| iPhone signing | ✕ | ✓ |
| Air gapAir-Gap: The device signs without a direct network or permanent USB connection to the PC - typically via QR code or microSD. Less attack surface, more steps to use. | ✕ | ✓ |
| OS firmwareOpen source firmware: Whether the device firmware (in whole or in part) is publicly viewable. More transparency - no automatic proof of absolute security. | ✓ | partial |
| RRP | EUR 149 | USD 177.94 |
| To the offerAffiliate links | No offer |
| criterion | BitBox02 Bitcoin-only | Coldcard Mk4 |
|---|---|---|
| Form factor | USB device | USB device |
| Display | monochrome | monochrome |
| SESecure Element: Special chip for key material according to the manufacturer. | ✓ | ✓ |
| BackupBackup: How to restore the wallet — typical seed phrase (BIP39), SLIP39 parts or a manufacturer-specific procedure. | Seed phrase ✓ · SLIP39 ✕ · Manufacturer backup ✕ | Seed phrase ✓ · SLIP39 ✕ · Manufacturer backup ✕ |
| Bitcoin | ✓ | ✓ |
| Ethereum/EVMEVM: Ethereum Virtual Machine — Chains and tokens that work with Ethereum-compatible wallets and apps (including many layer 2). | ✕ | ✕ |
| Solana | ✕ | ✕ |
Conclusion — Strengths, limitations and suitable uses. Your workflow and the functions it requires are what matter.
BitBox02 Bitcoin-only and Coldcard Mk4 are restricted to Bitcoin. The key question is whether you want to sign over USB with a companion app or through a separate PSBT and microSD workflow. A USB connection does not mean the seed must leave the signer.
BitBox02 Bitcoin-only offers open firmware, BitBoxApp and microSD backup. It supports desktop and Android over USB; iPhone signing, Bluetooth and an air-gapped mode are absent.
Coldcard Mk4 suits PSBTs and a separate wallet client. Its firmware code is readable, but the licence includes a Commons Clause restriction. For an existing device, Coinkite’s advisory about affected older seeds matters: a firmware update alone does not repair those seeds.
The recorded EUR 149 and USD 177,94 do not form a final-price comparison without a common currency, shipping and taxes. Decide on your signing and backup workflow first, then compare actual offers.
PSBT means a partially signed Bitcoin transaction exchanged between wallet software and the hardware wallet. This additional step must suit your usage; it does not replace a correctly configured backup.
