After a long time I have returned with yet another BIOS-related issue that is beyond my capabilities.
I was attempting to upgrade my friend’s FX553-VD with a new 120Hz display (N156HHE-GA1) and this machine came from factory with 60Hz display. Firstly I swapped displays in situ while machine was running to verify the display worked, which it did.
Once I rebooted the machine, I had a black screen. If I attached the old half broken display, it worked again… And then if I swapped the new display after booting with the old one attached, that also worked…
So I thought potentially it is a BIOS issue as the BIOS and POST screens are not visible on the 120Hz display at all, nothing showing up in Device Manager etc…
I tried downgrading BIOS to 2017 (308->302) thinking there was potentially a panel whitelist, this allowed the machine to sleep and wake up with the new display swapped but would be dead again after a reboot. This situation is very bizarre as the ROG variant (GL553VD) is documented to work with this 120Hz display, and the two machines are basically identical (they even have the same BIOS and model name in software). And the display works, but only if the system is booted with the old display.
Let me know if you need full dump or if the regular BIOS update file will suffice as I’m not too keen on ripping the whole machine apart, I can do it and I have a flash programmer but it would be annoying to take apart.
Those mulit model notebook bioses often have several video configurations stored, for me it’s uclear how they decide which to use. In addition this machine has an additional Nvidia graphics chip, having it’s own firmware.
One could think of replacing all these configs stored in Vbios and GOP VBT with the ‘right’ one and see if it works, they should normally have same size. Next problem is legacy boot (VBios) or UEFI (GOP driver and GOP VBT). In addition this machine has an additional Nvidia graphics chip, having it’s own firmware.
Never got changing GOP VBT settings to work properly for an IVB notebook (just processor graphics!). In addition you’d have to flash the bios chip most probably with a programmer several times. Depending on how easily accessilble the chip is, there’s a risk of damaging the hardware during disassembling.
UBU output
Manufacturer - ASUSTeK COMPUTER INC.
Model - GL553VD
BIOS release - 5.12 04/29/2019
BIOS platform - AMI Aptio 5
VBIOS in GUID 58B6E809-808B-4C26-BC0A-BFD7B770D721 VBIOS in GUID B981F167-9D2B-4CA0-82E9-63DF0E3C3BF3 VBIOS in GUID 9AECBA5E-37ED-4A37-83C7-0F73FB34B5DB VBIOS in GUID B92571E7-739B-4B2C-B6AF-CEC02A209C86 VBIOS in GUID 9B703B6F-90B2-4E8A-A80B-932ECD1F8801 VBIOS in GUID A0327FE0-1FDA-4E5B-905D-B510C45A61D0 VBIOS in GUID A0327FE0-1FDA-4E5B-905D-B510C45A61D0 VBIOS in GUID A0327FE0-1FDA-4E5B-905D-B510C45A61D0
OROM in GUID 365C62BA-05EF-4B2E-A7F7-92C1781AF4F9
Thanks for the quick reply
I didn’t quite understand how I would go about figuring out which Vbios/VBT config is the correct one. The ROG (GL553VD) version is not owned by me, it was just an example on Youtube. There are 3-4 videos showing this panel working with GL553VD so I am confused as to why this is not working.
I tried reading the EDID of the 120hz panel by hotswapping it into the T440p and attempting to poll the i2C buses but got nothing. Meaning I couldn’t backup the current EDID. But it worked with my T440p’s panel (N140HCE-EN1) hotswapping it back
Also my T440p would have a black screen on startup, eventually once in the OS it would go in a weird cycle of initialising, turning on the backlight (all with a black screen), and then turning off the display. If I couldn’t read EDID I couldn’t edit EDID to fool the FX553VD into thinking it was the original display, which could then be forced to 120hz in the OS. So that idea won’t work either.
I think I may have a defective panel as I cannot read the EDID at all - this might be why both my T440p and my friend’s FX553VD have a black screen on boot and act as if the monitor does not even exist.
Let me know what you think.
Lost_N_BIOS hasn’t been here since last year, unfortunately…
Might be a defective panel, might be a fake copy (most of the displays you can buy online I’d assume), might be an incompatibility as written.
That’s what I wrote, the different Vbios and GOP VBT stored in the bios have settings stored that are compatible to certain displays and hardware configurations. Bios firmware decides corresponding to model number (or another switch) which to load.
So either it’s a bad display, not presenting correct EDID information, or it’s a display that presents EDID information that’s not compatible with the vbios or bop vbt configuration loaded.
Try if the display works as expected on a GL553VD…
My only confusion was that the bios image for FX553VD seemed to be identical to bios image for GL553VD (as in they even have same model code) so trying to flash GL553VD bios would be pointless, but you cleared it up for me thanks
The seller agreed to exchange the panel for a different one, I’ll see if it works with the exchanged panel before I go deeper into VBT/VBIOS configs
Afaik the firmware doesn’t care what model screen is plugged in, I’ve upgraded laptops with screens they never came with, just random ones I have around, maybe the backlight isn’t working because of higher inrush current triggering OCP? That would explain the
black screen on startup, eventually once in the OS it would go in a weird cycle of initialising, turning on the backlight (all with a black screen), and then turning off the display.
Is there an image on the screen/does it initialize or visibly do anything if you look at it with a flashlight from behind?
Also hot swapping lcds is scary, the connector could send backlight voltage to the data lines killing mux if present and or cpu/gpu and or blow the backlight circuit on the laptop
Props to the seller for lending you a replacement tho