Codex Patches Samsung Monitor Firmware to Add Custom Crosshair

manikfox · reddit · 2026-08-19

The author used OpenAI Codex to hack the firmware of a Samsung Odyssey G9 monitor, replacing the built-in crosshairs with a simple center dot.

Technical Details:

Codex generated a minimal binary patch (13 bytes difference) based on Samsung's 1008.2 firmware.
Version Spoofing: The version was changed to 1009.3 to trick the monitor into accepting it as an upgrade.
Function Override: All six virtual aim options were redirected to a single 7x7-pixel center graphic already present in the firmware.

Outcome:

The patched image passed checksum validation and was successfully flashed.
The monitor now displays a hardware-layer center dot without requiring any software overlay on the PC.

Warning: Using unofficial firmware carries the risk of bricking the device.

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