User guide

On startup, BitFloppy creates a 1.44 MB USB storage drive containing the files needed for its wallet workflow.

Security notice: BitFloppy is a proof of concept. Use testnet or signet only—never real funds.

Board status

• UNKNOWN — a new board; it becomes EMPTY.
• EMPTY — no secret material; a secret is generated and the state becomes LOCKED.
• LOCKED — public wallet files are available.
• UNLOCKED — wallet files, including secrets, are available.
• CUSTOM_EMPTY, CUSTOM_LOCKED, CUSTOM_UNLOCKED — equivalents for user-provided seed material.
• FORMAT — removes existing data, then returns to EMPTY or CUSTOM_EMPTY.

Files on the drive

The device creates network.txt, log.txt, and README.txt. When unlocked, it also exposes mnemonic.txt and passphrase.txt.

The bip44, bip49, and bip84 folders contain derived addresses, change addresses, extended public keys, and—only while unlocked—private key material.

Initialize

Initialization is automatic. After the initial file generation, the board appears as mass storage. Files are regenerated on every reboot, so deleted generated files return after restarting the device.

Unlock private material

1. Create a file called UNLOCK.txt on the BitFloppy drive.
2. Unmount or safely eject the drive.
3. Restart the board.

The regenerated files now include the mnemonic, passphrase, and private-key data. Treat this state as sensitive.

Sign a PSBT

1. Create PSBT.txt containing the base64 PSBT.
2. Unmount or safely eject the drive.
3. Restart the board.
4. Retrieve the generated PSBT_signed.txt.

Signing unlocks the board, so handle the device and generated files carefully. For wallet setup, see Sparrow integration.

Reset or use a custom seed

1. Create FORMAT.txt.
2. Optionally add MNEMONIC.txt and PASSPHRASE.txt.
3. Optionally add NEWTWORK.txt to select testnet; omit it to use the default network.
4. Unmount or safely eject the drive, then restart.

The board removes its previous information and generates or imports the new secret material.

Supported hardware

Lolin S2 Mini ESP32-S2

Supported board: Lolin S2 Mini. Follow the firmware flashing guide to prepare it.