Lenovo 15ARH05 LCD whitelist removal request (Yes. display whitelists....)

[techcraze]

Long story short. i am building a fully custom car radio. and want to use a extremely bright LCD.

sadly the DGPU seems to be nonfunctional after i fixed the bios (fried voltage controller). so the Original HDMI port does not work.

you can use a EDP TO HDMI adapter to add a HDMI port as replacement to the onboard EDP LCD connector,

HOWEVER it turns out. lenovo enforces a LCD whitelist.

this means you cannot upgrade the LCD despite matching EDP specs and voltages.

If i connect a new screen directly to the system. only static shows. despite matching EDP 1.4 spec and Voltages


if i use a "EDP TO HDMI" adapter board. the screen will not work. unless you sleep/wake windows. then it does work.



this means there is a LCD whitelist. because on boot. EDP handshake occours. bios says NO. and blocks it.

in windows during sleep/wake. EDP handshake occours. but BIOS does not enforce whitelist in that moment.


I am wondering. can Bios LCD whitelist be removed Entirely? can the bios just be set to output 1080@60hz? (or 4k60hz. both work for me as my panel accepts both.)

if it cannot be removed/disabled. is there a way to replace a existing LCD for a different LCD model so it does work?

I have attached the bios flash that boots on this specific machine. thank you in advance for you help!

[techcraze]

if no modification is possible.

what are ALL the supported/whitelisted LCD's in my bios?

i can maybe try to spoof the EDID of my HDMI display. since both are BOE panels. just diff model types.

[techcraze]

Seems like something went wrong on my first post and the bios did not get posted on my post.

here is the original bios that works after reflashing.

[techcraze]

i did some testing while remoting into the machine with teamviewer so i can interact while blind,

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

despite the original screen not being connected. i think the system report's it's EDID on boot. (bios injects it?)


When i dug into the bios files. i found a module called "EDIDOverrideDXE" but i cannot make much sense of what it exactly is with a hex editor.

if anyone could shred some light on wth is going on with this bios?