"modernizing to HDMI" by writing EDID into ~2012 DualLink-DVI-only 2560x1440 display

Hello! I have a 2012 DualLink-DVI-only 2560x1440 display - the "No scaler, no menu, no overclocking, no audio, but not-bad panel" variant of Yamakasi Catleap Q270 27"

It was going to become unused since only selected GPUs can provide DualLink-DVI signal (the last one are some variants of RTX 3050 and RX5500 I suppose). The classic solution is "use active DP->Dual DVI converter or forget about it" but I was interested in checking how it would behave given a higher frequency single-link input with a passive hdmi->SIngle DVI cable. Thanks to ToastyX we have a great "EDID writer tool" and the good news are that at least my instance had NOT write protection on EDID EEPROM.

Result: it works fine in 35-55Hz range for 2560x1440; 60Hz was sometimes unstable in my experience. So "a monitor that can't be plugged anywhere" is turned into "55Hz hdmi 1440p monitor" given passive cable and 5 minutes for EDID flashing.

I performed several experiments and attach .zip with several EDID variants
  EDIDModToFixDualLink-2025.2.zip (Size: 75.91 KB / Downloads: 7)

• recommended 40-54Hz YamakasiQ270-54HZ2025.1-edid-256byte.bin
  EDID with a 3 entries for 40-50-54Hz. The 40Hz kept for compatibility with booting stage of integrated intel GPUs, since having only faster entries with 165+Mhz pixelclock caused "no monitor" beeps from intel GPU and "no picture until windows is loaded". So, after booting to desktop with this EDID - increase the frequency via standard windows settings.
• failsafe 40Hz-only YamakasiQ270-ANY40HZ2025.1-edid-256byte.bin
  EDID with a single 40Hz entry, fitting in pre-HDMI 165Mhz pixelclock limit. This variant should provide maximum compatibility with different signal sources, especially sources not capable of providing >165Mhz pixelclock
• experimental 40-60Hz YamakasiQ270-60HZ2025.2-edid-256byte.bin
  EDID with a 5 entries for 40-50-54-56-60Hz. Similar to the recommended variant but with higher frequencies. It's experimental, so have caveats:
  • 56 Hz uses same ~217.5Mhz pixelclock similar to 54Hz mode, but absolutely reduced blanks still handled by a specific monitor model. Blanks are so small that while it is listed&works on Intel and Nvidia, the AMD driver excludes this mode from an available list treating is as "unbelievable")
  • 60 Hz with 241.5Mhz pixelclock is not very stable in my experience. With some sources it "works almost always" but for most others it sometimes gives a black screen, and only 3-4 poweroff-wait-on by the monitor button gives the monitor the ability to sync with input signal and start displaying
    

Since my monitor was "just writable" - after writing those EDIDs it start be useful with any signal source, no ClockPacther/CRU needed. In theory if some similar monitors are not writeable - those EDIDs can be activated another ways:

• via importing it in Custom Resolution Utility
• Or to avoid effect of "picture not visible before OS boot" - the writable EDID EEPROM can be injected in the form of a trivial extra device that provides only writable EDID and the the video signal is passing through. The so called "HDMI lock emulator" in the role of writable-EDID-injector between signal source and HDMI cable. Cheapest one is in a picture below (no need to disassemble it; internals are shown below just for reference). Write EDID into it and always use the monitor with this emulator.
  

A bit more obscure cases like writing EDI via Linux on integrated intel GPU presented at the project page