Resolution setting for Philips display broken

[billsouthworth]

I've been using BetterDummy for a year or so successfully with a 49" Philips 499P9, recently on an M1 Max Macbook Pro. Originally I used a dummy to set the resolution to 5120x1440. More recently, I've been resetting the native resolution successfully. I've had a couple of software updates happen recently including an update to Monterey 12.5.1. Somewhere along the way, things have broken and I can no longer get the display resolution on the Philips to go above 3840x1080, no matter what I do. I've re-installed the latest BetterDisplay 1.2.9 Pro. I've tried creating a dummy to set the resolution. Tried to reset native and default without the dummy. And with the dummy. Nothing works.

[billsouthworth]

Also, I have had an issue with the Philips flickering sometimes when I first startup, and requiring a reboot to get a stable display.

[billsouthworth]

Oh yeah. Right along I've been using this with the HDMI Port.

[waydabber]

Hi @billsouthworth - if you are using native smooth scaling, the max. horizontal resolution for M1 Pro/Max/Ultra is 3840. If you are using dummy mirroring, there is no such limitation. In the latter case make sure that you are mirroring the dummy to the screen, not the other way around. If you post a screenshot about how your menu looks like and what do you see under Settings/Displays, I might help you out.

The HDMI port of the M1 MBP is a pain, if you can, I'd advise you to use USB-C/DisplayPort. This is also required for DDC brightness control to work.