Video output completely black when setting Discrete(Ultimate) mode on Asus TUF Dash F15 FX517ZR

Hello.

This behavior happens whenever I try to switch from Optimus to Dedicated using either asusctl or rog-control-center.

If I set the GPU mode to Dedicated, the entire screen goes black and it only starts providing output after I log in on X. Luckily I have configured sddm to autologin my user so, I only have to touch type my luks password.

From the boot up, even the "Asus in search of incredible" logo is missing, and I have to type my luks password without really seeing the screen. If I try to reach out Setup by pressing F2, nothing is shown on screen so I can't see if it is asking my master password or not.

Another detail. If I boot up with no HDMI or DP cable connected, built-in screen will still be missing after X login. If there is an external monitor connected, X will by default mirror everything and after that I'm able to adjust using xrandr. But the laptop will become useless on situations where I want to use only the built-in screen.

Firmware is also up to date, and the same behavior happened on versions 316 and 315 of the UEFI Firmware.

Is there any output I can provide from this laptop to help investigating this issue?

System details:

nwildner@sandworm ~]$ sudo dmidecode -t bios| grep -i 'version\|release'
  Version: FX517ZR.317
  Release Date: 05/03/2023

Steps to reproduce:

Apply the dedicated(ultimate) mode with asusctl bios -D 0
reboot

Workaround:

Revert to Optimus mode with asusctl bios -D 1
reboot