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Crypt-in

Flash Guide

Supported Hardware

Section titled “Supported Hardware”
  • ESP32-S3-WROOM-1 (any flash size)
  • USB-C cable connected to the native OTG port (NOT the CH343/flash port if your board has two)

Download

Section titled “Download”

Latest firmware: cryptin.lake8.dev/download

Verify the signature before flashing:

Terminal window
# verify with lake8.dev public key

Flash via Crypt-in App (Windows)

Section titled “Flash via Crypt-in App (Windows)”
  1. Open Crypt-in Personal app
  2. Connect ESP32-S3 via USB-C (OTG port)
  3. Click Flash Firmware
  4. Select the downloaded .bin file
  5. Wait for completion

Flash via CLI

Section titled “Flash via CLI”
Terminal window
pip install esptool
esptool.py --port COMx write_flash 0x0 cryptin-firmware-vX.X.X.bin

First Boot

Section titled “First Boot”

On first boot, the dongle generates:

  • Ed25519 keypair (K_identity)
  • K_attestation from hardware entropy
  • BIP-39 seed (24 words)

The seed is shown once via serial (UART0/CH343 port). Write it down immediately — it will never be shown again.