Hardware Wallet Seed Phrase Backup: BIP39 & SLIP39

A wallet backup lets you restore access after losing a device. It needs to be complete and compatible with the backup method you used. This guide explains BIP39 words, SLIP39 shares and additional passphrases, then helps you identify which information must remain available for your particular wallet.

BIP39: words, order and checksum

BIP39 describes how a generated word sequence is converted into a seed. The sequence includes a checksum; it is not a freely chosen memorable sentence. Configurations may use 12, 18 or 24 words, for example. Recovery requires the correct order and any additional passphrase. The wrong order can produce an invalid backup, so not every input automatically opens another usable wallet.

• Never photograph seeds or save them to cloud notes.
• Consider metal backup or equivalent fire/water resistant (follow manufacturer’s instructions).
• Write down the words in the order specified by the device. A swapped word is often a different wallet.
• Do not treat the device as a single copy after setup. It can be lost.

You can find device information for BIP39/SLIP39 in the Comparison table and on the product details, e.g. b. Coldcard Mk4 or BitBox02 Multi.

No one reputable needs your word list to “help.” Real support doesn't ask for seed, PIN or remote access to the device.

SLIP39: recovery using a threshold

SLIP39 divides a backup into cryptographically generated shares. Recovery requires the configured minimum number of matching shares. It differs from BIP39 and is not equivalent to splitting a word list yourself. Check the replacement device and the original group and threshold configuration. A documented method only helps if the required shares can actually be brought together when needed.

In practical terms, 2-of-3 means: Two parts are enough for restoration, one part alone is not. That shifts the problem - you have to choose places and people so that two parts come together in an emergency, but are not in a drawer in everyday life.

Card duplicates and manufacturer cloud backups are different contracts again. Read them for what they are: a second path with its own failures, not as invisible magic.

Passphrase

An additional BIP39 passphrase changes the wallet derivation. It is not a PIN and need not be a single word. Only the same word sequence and passphrase lead back to the intended wallet. A different input can open another wallet that appears empty. Plan passphrase storage separately; a complete backup of the words does not automatically contain it.

Passphrase is complexity. It makes sense if you document the process - and risky if you only have it “in your head”.

Air gap and PSBT

Air-gapped workflows (e.g. MicroSD/PSBT) reduce online exposure but increase process overhead. They do not replace seed backup. A device that is never connected to the mains still needs a fuse that can withstand fire, moving and inheritance.

What we consciously do not claim

• No “we tested 20 recoveries” stories.
• No guarantee that your backup setup is correct.
• Not investment advice.

Next: Buying criteria, explanation, What protects the device, Methodology.

BIP39 and manufacturer's own ways

BIP39 is the open standard: a word list from which keys are deterministically derived. Many devices use it. Anyone who has the words in the correct order can restore on another compatible device - as long as no extra passphrase is missing. The specification is in BIP 39.

Manufacturer's own ways are other contracts. A duplicate card, a cloud backup behind an account, a microSD just for this model: This can be convenient and still tie to the brand. Before you buy, ask yourself: Can I restore without this case - and is that in the documentation, not just in the unboxing video?

Both can coexist. Some devices offer BIP39 and a second way. The second way is not an invisible web; he has his own failures (account, card loss, proprietary software). In the Comparison table The procedures are presented as cells, not as a grade of “modern”.

SLIP39 remains the specified route for shares (SLIP-0039). Half BIP39 lists without Shamir are often more uncertain than they sound. Card formats without a classic display impose the same test: you must be able to explain the brand's recovery path before inventory is placed on it.

metal and paper

Paper is the documented entry: words by hand, without photos, without the cloud. It does not tolerate fire and long periods of water. Metal plates and stamping systems promise just that — fire and water resistance — and come with their own flaws: wrong order, illegible embossing, a set you never practiced.

We have not conducted our own fire tests. Manufacturer's instructions and the choice of materials are information, not a laboratory grade from us. Metal is not an upgrade from the seed; it is a different carrier medium of the same words. If the plate is next to the device in the same drawer, you have laid the separate storage area flat again.

Digital remains digital: screenshot, password manager sync, chat, email to yourself. Files are copied. The default path in the manufacturer's documentation is offline - not the safe folder in the cloud.

If the fuse is missing

Distinguish which access remains after losing a device or backup. A broken device with a complete compatible backup differs from a usable wallet without one. An exposed backup also raises the question of access by third parties. The following cases help classify the situation; the actual recovery procedure depends on your model and backup method.

1. Device broken or wet. Without a complete backup or other usable access, recovery may be impossible.
2. Device lost, backup available. You buy a compatible device and restore. To do this you need to have read the route beforehand - not in a panic.
3. Fuse found by someone else. Anyone possessing the complete recovery information may also gain access. That includes any passphrase used; the device PIN does not replace this protection.

Inheritance is an organization, not a product recommendation: a security that no one can find is lost for heirs. A fuse that lies around in everyday life can be found for others. What else protects the device at this moment is stated What a hardware wallet really protects: the key in the chip, not the open word list.

Before inventory is transferred to a new device, the recovery path belongs in the manufacturer's documentation - not in the unboxing video alone. BIP39 on a second compatible device is a different contract than a duplicate card or microSD for this model only. The cell is in the Comparison table; Examples in details: Coldcard Mk4, BitBox02 Multi. We do not claim any recovery testing of our own.

Metal next to paper is not a second secret if both are in the same place. Separate locations, legible order, no photo: that's the organization. The words themselves remain BIP39 or the manufacturer's own way — not the record.

How to review your backup plan

First record only the backup method, device model and location of the official instructions. This overview needs no words, PINs or passphrases. It should make clear which backup is required and which compatible recovery methods are documented.

Then consider separate failure modes: losing the device, losing a storage location and unauthorized access. Additional copies at different locations address different failures, but also add places where a backup might be discovered. With shares, the required threshold must remain attainable.

Include any passphrase explicitly in this plan. Use recovery-check functions only as described by the manufacturer and preserve existing access until the complete backup process is understood. The lost or broken hardware-wallet guide covers specific emergency situations.

Frequently asked questions