Seed backup checkup

Why it matters. A seed is only as strong as the randomness used to create it. In July 2026 a Coldcard firmware bug made some seeds guessable, and updating the firmware did not repair them (Coinkite). Checking takes two minutes.

If yes: Follow your maker's advisory for that flaw. When an advisory says the seed itself is weak, the fix is a new seed and moving your funds, not a firmware update. Coldcard owners: use the two-minute Coldcard check.

If not sure: Look up your device or app on our security advisories page and on your maker's own security page. Coldcard owners: use the two-minute Coldcard check.

Why it matters. A backup you have never tested is a guess. One wrong or unreadable word can lock you out, and you only find out when you need it. The test that counts starts from your paper or metal copy, not from what the device already knows. The safest way is your device's built-in backup check, where there is one (Trezor's is an example), because it erases nothing. Otherwise restore from the copy on a second hardware wallet and check that you get the same wallet fingerprint or first receive address. Don't reset the only device that holds your wallet to test a copy you have never tested.

If no, or not sure: Test your backup with your device's built-in backup check, or by restoring it on a second hardware wallet. Don't reset the only device that holds your wallet to do it, and never test by typing the words into a phone, computer or website. Step by step: how to test your seed phrase backup.

A passphrase is extra text you chose yourself, on top of the seed words, that opens a separate wallet. It is not your PIN.

Why it matters. Every passphrase opens a valid wallet, even one with a typo, so the wallet cannot warn you when you get it wrong (BIP-39). Forget it, and nobody can recover the funds: not the maker, not us. Coinkite's advice is to back it up exactly and separately from the seed (Coldcard).

If no: Write the passphrase down exactly, with every capital, space and symbol, and keep it in a different safe place from the seed words. Then check that it still opens the wallet you expect. More in our passphrase guide.

If not sure: Find out whether your wallet uses a passphrase. If you never chose extra text on top of the seed words, it doesn't. If it does, write the passphrase down exactly and keep it apart from the words. More in our passphrase guide.

Why it matters. A single copy can be lost to a fire, a flood, a move or a well-meant tidy-up. A second copy in a different place covers that. Every copy is also one more place where someone could find it, so keep each one as well protected as the first.

If no, or not sure: Make a second copy by hand and keep it in a different safe place. Don't photograph, scan or print it.

That includes notes apps, email, cloud storage, screenshots and photos.

Why it matters. Anything that has been on a connected device may have been copied by malware, a cloud backup or a fake website. Fake websites that ask Bitcoin users to type in their backup phrase have been around for over a decade (Blink, August 2026). Trezor's advice: if you suspect your backup has been compromised, assume it has, and move your funds (Trezor).

If yes: Treat the seed as exposed. Move your funds to a wallet with a brand-new seed, ideally made on a second hardware wallet, then retire the old words for good. With only one device, follow your maker's guide for that case before you reset anything (Trezor's step-by-step guide shows the process). Deleting the photo or file is not enough, because copies may already exist elsewhere.

If not sure: If you can't rule it out, the safe choice is the same, done calmly: move your funds to a wallet with a brand-new seed, ideally made on a second hardware wallet, before you reset anything.

Why it matters. Every piece gives away part of the secret, so whoever finds one has far fewer words left to guess. There are standard ways to share a backup safely: Shamir shares under SLIP-39, where fewer than the required number of parts does not leak information about the master secret, and multisig.

If yes, or not sure: See how much each piece gives away with the seed split risk tool. If you change your setup, build and test the new one before you move any funds.

Why it matters. One maker's bug can hit all its devices at once: in the 2026 Coldcard case, a multisig made only of affected devices stayed exposed (Block). For small amounts, one good device is fine. Every extra setup is also a new chance to make a mistake.

If yes, or not sure: No rush. Read why three keys from the same vendor are not multisig, then decide whether the amount justifies keys from different makers.

Why it matters. Without instructions, a family may never find the funds, or may lose them by guessing. A hardware wallet can erase or lock itself after too many wrong PINs: a Coldcard, for example, bricks itself for good after 13 failed attempts (Coldcard).

If no, or not sure: Write a short letter for someone you trust: what you have, where your instructions are kept, not to guess PINs, and that nobody genuine will ever ask for the seed words. Keep the seed words themselves out of the letter. For the legal side, ask a lawyer or notary where you live; we don't give legal advice. Planning options: seed phrase inheritance.