[dxld]

OP's approach looks cool but a bit baroque. I'm also hacking around EDID issues and it turns out there's a nice GUI program to decode and (lightly) patch it: https://packages.debian.org/unstable/utils/wxedid

I have to do more involved full EDID reconstruction surgery tho since I need to add DTD entries rather than just change existing ones. So I'm looking at [edid-generator] together with [cvt12]. The latter can calculate xrandr modelines for VESA standard timings that all seem to work with my TV. cvt12 adds the option to calculate NTSC (1/1.001) timings over regular cvt which is already in Debian.

[cvt12]: https://github.com/kevinlekiller/cvt_modeline_calculator_12

[edid-generator]: https://github.com/akatrevorjay/edid-generator (thanks Kodi wiki)

[kj800x]

I genuinely take the baroque comment as a complement. There's many paths to a solution and this was a fun one that ended up working for me.

Thanks for the pointers for those programs. Someone else pointed out Kaitai Struct could help me do the hex editing which I'm planning on taking a look at later

[nyanpasu64]

I tried wxedid from the AUR on Arch Linux, but unfortunately it segfaults in Wx code on startup. I haven't tried building it manually and debugging.