# open-picpak: reconstructing the PicPak frame's BLE protocol and device behavior

> open-picpak documents the PicPak 4.2-inch e-ink frame's stock firmware behavior, BLE GATT protocol, and image conversion pipeline. The author reports deriving byte-level findings from the stock ESP-IDF image and a device client, then using those findings in custom ESP-IDF firmware, host tools, and a self-hosted backend.

- Type: Case study
- Targets: Firmware · Protocol
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-06
- Added to the catalog: 2026-11-06
- Original resource: <https://github.com/GottZ/open-PicPak>
- Primary source: <https://github.com/GottZ/open-PicPak/blob/7b76daab2219b0a1c061fbe9fbf91747a8961954/documentation/ble-protocol.md>
- Catalog page: <https://awesomerea.org/resources/open-picpak-case/>
- Record JSON: <https://awesomerea.org/resources/open-picpak-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/open-picpak-case/index.md)

## Requirements & limits

- **Prerequisites:** A PicPak e-ink frame is needed for device use and hardware checks.
- **Limits:** Firmware and backend development remain in progress; the web-usb component is not public.
- **License:** MPL-2.0 license.

## Primary sources

1. <https://github.com/GottZ/open-PicPak/blob/7b76daab2219b0a1c061fbe9fbf91747a8961954/documentation/ble-protocol.md>
2. <https://github.com/GottZ/open-PicPak/blob/7b76daab2219b0a1c061fbe9fbf91747a8961954/README.md>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.