BOWSER, DIY BITCOIN HARDWARE WALLET (BETA)

Building your own hardware wallet is a bit like building a lightsaber, only really necessary if you want to be a Jedi.

Now building hardware wallets is easy with the help of uBitcoin an Arduino library created by Stepan Snigirev.

Building hardware wallets not only gives greater autonomy/liberty, it is an excellent excuse to get a deeper understanding of how bitcoin keys, seeds and signing works.

Tutorial

https://www.youtube.com/watch?v=DG1zrlAVdys

SD COMMANDS

Commands to enter into bowser.txt on the SD card.

Wipe device completely, setup new wallet:
HARD RESET

Restore from a seed backup:
RESTORE husband behind shallow promote....

Sign an Electrum transaction:
SIGN 45505446ff00020000000001016cb....

Installing Arduino

Install Aruino IDE https://www.arduino.cc/en/Guide/HomePage

Install ESP32 Boards https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md

Libraries Used

• uBitcoin (Download library from github and "Add Zip Library" in Arduino Library Manager)
• M5Stack (Install from "Library Manager" in Arduino)
• lvgl (Install from "Library Manager" in Arduino, search as "lvgl", appears in the list as "lv_arduino")

Materials

• M5Stack (grey one is better)
• SD card (not sure if size is an issue for larger SD, 16GB works fine)