Zephyrus G16 GA605WI Screen at highest brightness and cannot adjust

[fsclsnow]

I just updated the myAsus and Armoury Grate. After restarting, the screen keeps at the highest brightness and has no way to adjust.

FN+F7 and F8 are useless. The Win11 control panel does not have a brightness adjustment bar.

Under device manager, unable to find the integrated graph card: Radon 890M.

I have called Asus tech support, but they are useless. I have tried hard shutting off during the call (pressing the power button for 60 seconds), but nothing has changed.

[Hera]

Dude, I have the same problem on my Asus rog Zephyrus g16 (2023) gu603zv 

When switching the system to ECO mode (integrated graphics) and rebooting, then switching to Standard mode (discrete NVIDIA GeForce RTX 4060 graphics), the brightness adjustment becomes unavailable. The brightness slider is present, but changes have no effect on the backlight level.

Temporary solution:

In Device Manager, I remove the NVIDIA GeForce RTX 4060 graphics card (without deleting the driver). The graphics card disappears from the "Graphics Processors" section and is displayed as a VGA-compatible device. After activating the VGA device, the screen briefly goes black and turns back on, after which the brightness adjustment is restored.

Additional information:

The issue occurs only after switching from ECO mode with a system reboot to Standard mode. The graphics card and integrated graphics drivers are updated to the latest versions.

[fsclsnow]

The root issue was the missing or misplaced integrated graphics driver. 

Mine is an AMD Radeon 890M. Neither the ASUS support website nor the Win10/11 provides the right driver.

You must download the driver from AMD. Then, the device manager can find the integrated graphics and resolve the issue permanently.