Lenovo 15ARH05 LCD whitelist removal

[sebaskitten]

Hello good day. seems like this lenovo ideapad has a LCD whitelist.

i connect compatible LCD. only static garble displays. (original 1080p@120hz. new lcd is 4k@60)

if i use EDP TO HDMI. then Display ONLY works when sleep/wake in windows first. not in boot.

likely EDID whitelist....

I have looked around bios. and LenovoVideoInitDXE does not exist i think. but i found a module called EDIDOverrideDXE. not sure what to do with it. since limited firmware modding experience.

Since this lenovo uses AMD ryzen 4600H. bios might differ from the old biosses i worked with prior.

Here is a copy of my bios which works if i reflash it using CH341 so it should be good. Thank you in advance for your help

https://drive.google.com/file/d/1u7S7cBw3GZagYDc1Z0PFVPiAdXVz8hUH/view?usp=sharing

Edited May 9 by sebaskitten

[sebaskitten]

i did some testing while remoting into the machine with teamviewer.

with the cheap 17 bucks EDP to hdmi converter. the EDID recieved by the machine is mismatched from what the actual connected screens EDID is.

despite the original screen not being connected. i think the system report's it's EDID???

If i use the 40 bucks Geekworm adapter. system never detects a display at all. no EDID.

[sebaskitten]

More testing later.

in windows the 4k screen works perfectly fine when connected directly to the laptop.

during boot there is a lot of static but no output. during windows boot when driver loads and correct resolution get's loaded.


i suspect the screen get's driven at 1080p@120 hz or smth odd in the bios?

Brightness controls work fine in windows. just no bios display due to garble.