Resolution overrides do not work in the pre-boot environment (FileVault, boot options, recovery etc)

[my-world-2022]

I have a mac mini m2.
After using BetterDisplay to modify the resolution, the display will display normally after powering on and entering the password to log in to the computer user. But before the computer user logs in, the resolution is still the original, so the screen cannot be displayed, how to solve this? How to use the modified resolution before logging in the user

[waydabber]

Hmm. Normally the default resolution should apply after probably the second reboot (the last used resolution should be applied). Unfortunately there is no clear and direct way to influence what the login screen resolution is. What resolution is chosen by the Mac now? I see you did override the native resolution - is there a reason for that?

[my-world-2022]

The native resolution of the display is 3840 * 2400, but it is recognized as 3840 * 2160 by the mac mini m2, sometimes it cannot be displayed.
After using better display and correcting the resolution, everything works fine. But in the login interface, it is often necessary to enter the password without seeing the screen.

[ACallander]

I'm having a similar issue to mine on my 4k monitor. When it wakes from sleep, it shows Generic Monitor and a super low resolution of 1024X768. When I turn the 4k off and back on it registers it properly. It is on my new Mac Mini M2 Pro but never occurred on my older MacBook Pro 15" 2018.

[waydabber]

Interesting. This seems to be an M2 specific issue maybe. I'll think about what could be done but the difficulty is that the app cannot run until the user is not logged in and the app is started, so it's rather difficult to deal with this problem. However display overrides should take effect at boot so it might be a macOS bug with these newer Macs.

[ACallander]

Let me know if there is anything on my end I can provide to help see if this issue can be solved.

[my-world-2022]

I found the reason, and it was solved by turning off the filevault function of mac mini m2.

Is there a way to have the login screen have the correct resolution when opening the FileVault feature?

[waydabber]

Oh, right, FileVault, forgot about that. FileVault is running at pre-boot and is not aware of display overrides. It should try to match the last used resolution if available in the default, non-overridden resolution table, but if it isn't, it will use the original native/default resolution. There is no way around that I am afraid. If you use your mini at home where the risk of theft is low, I'd just disable FileVault, otherwise try not to restart your Mac often, put it into sleep instead. Entering password in blind is not optimal, but sometimes necessary with FileVault, this was the case with many eGPU setups on Intel as well, where GPU support was not available in the pre-boot environment.