FriendlyELEC-Forum

When I set the output resolution to 4K@120Hz in Android 12/14/TV, the screen shows significant display abnormalities (e.g., flickering, visual artifacts, or signal instability).But it works fine on Ubuntu Desktop, I checked the wiki and found that this problem has been fixed on Linux:

19.23 2024-05-22
19.23.1 Linux Kernel
Fixed the issue where HDMI output at 4K 120p was displaying incorrectly.

I returned the M6 ​​and bought the R6C instead, but the same problem occurred.So I think it's not a hardware issue but a system problem.

The changelog fix you referenced (19.23.1 Linux Kernel) was pushed specifically for the Linux releases. It is highly likely that the FriendlyELEC development team hasn't merged those specific HDMI timing patches into the Android kernel tree yet, or there is an issue with the Android Hardware Composer (HWC) failing to properly negotiate the 120Hz signal. The RK3588 Android SDKs occasionally lag behind the standard Linux builds for specific display fixes.
nullsbrawl
For now, why not cap your refresh rate at 4K@60Hz in the Android settings. It’s not ideal if you need the 120Hz, but it will stop the flickering and visual artifacts so the device is usable.

Thanks for sharing this. The fact that 4K@120Hz works correctly on Ubuntu but shows display issues on Android strongly suggests that the hardware is capable and the problem is likely related to the Android firmware or HDMI driver implementation. Since you experienced the same behavior on both the M6 and R6C, it doesn't appear to be an isolated hardware fault. It would be helpful if the Android builds could include the same HDMI fixes that were already applied to the Linux kernel. Hopefully the development team can confirm whether this fix is planned for a future Android update.