MacBook Neo + Custom Resolutions - findings

[szx7986-oss]

Native flexible scaling does not seem to work on my MacBook Neo.

For this test, I am not using a virtual screen and I am not using any custom EDID override. The external display is connected normally via USB-C to DisplayPort.

After enabling:

• Edit the system configuration of this display model
• Enable flexible scaling

then applying the changes and rebooting, BetterDisplay still does not unlock flexible HiDPI scaling for this display.

The only HiDPI mode available is 1280×720 HiDPI, which is already available in macOS without BetterDisplay. So it looks like enabling native flexible scaling has no effect on this machine.

Hardware

• Mac: MacBook Neo
• GPU shown in System Information: Apple A18 Pro
• Display: Philips PHL24M1N5500Z
• Native display resolution: 2560×1440
• Connection: USB-C to DisplayPort 1.4
• Normal refresh rates available: 120 / 144 / 165 Hz

Expected behavior

After enabling native flexible scaling and rebooting, BetterDisplay should unlock flexible HiDPI scaling for this natively connected 2560×1440 display, with a working resolution slider / additional HiDPI scaling options.

Actual behavior

Only 1280×720 HiDPI is available.

No additional flexible HiDPI scaling options appear, and the resolution slider does not allow custom HiDPI scaling.

Comparison

The same BetterDisplay workflow works correctly on my MacBook Air.

Notes

For this test:

• No virtual screen is used
• No custom EDID override is used
• The display is connected natively
• Both native flexible scaling options are enabled
• The system was rebooted after applying the settings

Could this be related to MacBook Neo / Apple A18 Pro detection, or to the display override not being loaded correctly by macOS on this hardware?

[szx7986-oss]

Additional diagnostic notes:

I also tested a custom EDID override as a workaround.

I attached two EDID files:

1. 01_original_DP_EDID_PHL24M1N5500Z.bin

   • Original DisplayPort EDID from the Philips PHL24M1N5500Z.

2. 02_modified_DP_EDID_4K60_3200x1800_60_75_90_HiDPI90.bin

   • Derived from the original DP EDID.
   • Adds CTA VIC 96/97 for 3840x2160p50/p60.
   • Adds CTA detailed timings for 3200x1800@60/75/90.
   • Keeps the original DP high-refresh 2560x1440 timings.

With the original DP EDID, native flexible scaling does not unlock additional HiDPI modes on this MacBook Neo. Only 1280x720 HiDPI is available.

With the modified EDID override:

• Adding 3840x2160p50/p60 makes 1920x1080 HiDPI appear.
• Adding 3200x1800@60 makes 1600x900 HiDPI appear.
• Adding 3200x1800@75/90 allows 1600x900 HiDPI at high refresh.

However, this custom EDID approach seems capped at around 90-92 Hz on this MacBook Neo + Philips display combination. A replacement test with 3200x1800@92 worked, but 94 Hz and above did not appear.

I also tested a virtual display mirror workflow. With a virtual 1600x900 HiDPI display mirrored to the physical monitor, I can reach 144 Hz. However, this is more complicated and less ideal than native flexible scaling because it depends on a virtual display/mirroring setup and may introduce extra issues with display identity, color management, sleep/wake behavior, full-screen apps, etc.

So the desired fix is still for BetterDisplay/native flexible scaling to work directly on this natively connected 2560x1440 display on MacBook Neo, without requiring a custom EDID override or a virtual display mirror.

BetterDisplay_MacBook_Neo_EDID_bin_only.zip

[waydabber]

Yeah, the A18 chip is basically geared to provide some display output to 4K TVs with iPhones - Apple probably mostly meant the Air to be used as a mobile device and did not do much to make external display support work very well. Ppl had some success with virtual screens though.