List of packages containing EDID binary files at $out/lib/firmware/edid. Such files will be available for use in drm.edid_firmware kernel parameter as edid/<filename>. You can craft one directly here or use sibling options linuxhw and modelines.

[ ]

[
  (pkgs.runCommand "edid-custom" {} ''
    mkdir -p "$out/lib/firmware/edid"
    base64 -d > "$out/lib/firmware/edid/custom1.bin" <<'EOF'
    <insert your base64 encoded EDID file here `base64 < /sys/class/drm/card0-.../edid`>
    EOF
  '')
]