Tools KindleCast - Stream your Windows desktop to Kindle PW4 over USB 25+ FPS, open source

[Joelkc]

TL;DR: I built KindleCast, an open-source tool that streams your Windows desktop to a jailbroken Kindle PW4 over USB at 25+ FPS. I started this because most similar projects were unfinished or not made for Kindles, so after months of development and iteration, I built a complete, highly optimized solution.

🎥 Demo: https://www.youtube.com/watch?v=6N9Lbz48ee0
📦 GitHub: https://github.com/joelkc/kindlecast

Why I built this
I created KindleCast for myself as a way to give my eyes a much-needed break. Spending hours staring at traditional emissive monitors was causing eyestrain, so I wanted to take advantage of the Kindle I already had. I now use it daily as a secondary monitor to reduce eye strain.



Core Features:
- Nitro Mask (DPSSM) & Flow Mask (HSM): Custom scanline masking algorithms designed for smooth motion on e-ink.
- Advanced Dithering: Includes IGN (used in God of War / Horizon), BN256, and BNHQ.
- Extras: Motion Sharp, CLAHE, dual zoom, backlight control, and a startup screen cleaning sequence.

Quick Requirements:
- Jailbroken Kindle PW4 (firmware 5.18.1) with KUAL and USBNetwork installed.
- Pre-compiled receptor binary (available in GitHub Releases).
- Windows PC with Python 3, dxcam, and opencv.

The README includes the full cross-compilation commands and flags if you need to compile the C receptor from source. It's fully documented, but if you hit any roadblocks with the toolchain setup, feel free to ask here or check the repository's guide.

Quick Tips & Disclaimers:
- Screen behavior: The screen flashes white on start (cleaning sequence) and fast-moving objects will leave some ghosting. This is an inherent e-ink limitation, but the custom masks make text and UI navigation incredibly usable for daily work.
- Flickering: If it flickers during heavy video or gaming, pause for a second until the screen stabilizes.

Recommended Settings:
- Nitro Mask: 25 FPS, CH4, 19% density, orient H
- Flow Mask: 35 FPS, NJ freq, orient H (Best with BN256, BNHQ or IGN)

In theory, this should work on other Kindle or Kobo models and different firmware versions with minor tweaks to the receptor resolution (FB_WIDTH/HEIGHT), EPDC addresses, and the Python script resize values — as long as the device supports FBInk.

If you manage to get it running on another model or firmware, let me know in the comments so we can update the compatibility list. Happy to answer any questions!

[dandaman]

Wait, this could work on Kobo? How?

[Joelkc]

EDIT (2026-05-29): Repository temporarily private — security hardening in progress
While reviewing the v1 code with fresh eyes I confirmed two issues I want to address before more people deploy this:

1. The UDP protocol has no authentication or source-IP validation — anyone on the same LAN can send frames or control messages.
2. The `CMD:` control message passes its payload directly to `system()` on the Kindle (running as root via the KUAL launcher).
In a typical home setup behind NAT this is not reachable from the internet, so existing v1 users on a trusted home network are not in immediate danger. The real concern is anyone who port-forwards UDP 5050, runs on a shared/public WiFi, or deploys this on a Kindle that's also doing something else sensitive.
Repo is private until I land:

* Whitelisted command set on the receptor (presets become enum'd actions, not arbitrary shell)
* Shared-token handshake + IP lock for the session
* SECURITY.md with the threat model spelled out
Will post here again when v2 is up. Thanks for the patience — happy to discuss the design of the auth layer in this thread if anyone has input.

[foxm]

Can you please share the repository ? Any ETA for when the work is done ? It's been a long time.

[Frogm4n]

It's been less than a week since the thread was started and 3 days since it was made private for security reasons. That is in no way a long time.

[MiskaDev]

Hey its taken down, could you please send me the source im really intrested
discord: miskadev