Black screen after refresh rate change

[iipeacefrog]

I have a hackintosh that has been extremely stable other than some laggy/jumpy mouse behavior. In an effort to troubleshoot the mouse issues, I changed my refresh rate to 27hz. This caused the screen to go black and I cannot seem to get it back. I've tried multiple boot flags (nvdisable, -x, -v) but nothing seems to work. I can boot into safe mode, but as soon as I log in (the screen shows up for login page), the screen goes black again.

I think my best bet is to manually modify the refresh rate setting using single user mode, with a defaults write command, but I'm not sure exactly which .plist file to write. Alternatively, I can mount the EFI partition from my windows 10 installation on the 2nd harddrive.

Any suggestions? I've also tried switching to the internal GPU, no dice...

My specs:
Vanilla install
Latest clover
Mojave 10.4.5
Intel 9900k
32gb ram
AMD radeon 970
Broadcom BCM94352Z

Monitor has HDMI in only.

 

[justinhe]

I changed my refresh rate to 27hz.

how did you change that?

 

[iipeacefrog]

It was one of the options in the display settings. 50hz, 60hz or 27hz...weird, I know.

 

[justinhe]

Boot to safe mode, and delete those files, reboot.

Sorry i see you even can't boot to safe mode, then boot to recovery mode, grab the terminal from top menu:

cd /Volumes/your startup disk name/Users/your username/Library/Preferences/ByHost/
rm -f com.apple.windowserver.*
rm -f com.apple.preference.displays*

 

[iipeacefrog]

Thanks! Will give that a try and see if it works

 

[justinhe]

Thanks! Will give that a try and see if it works

command updated...
those command deletes the display settings, macOS will rebuild them.

 

[iipeacefrog]

When I try to delete the window server file I get "read only file system". I've tried sudo and modifying permissions but no luck. This is such a silly problem. Any advice?

 

[iipeacefrog]

Got it. Had to mount using sbin/mount -uw. Also, the display pref is in the main library folder not the user subfolders. Back in action. Now to fix this laggy mouse...

 

[roromush]

Got it. Had to mount using sbin/mount -uw. Also, the display pref is in the main library folder not the user subfolders. Back in action. Now to fix this laggy mouse...

I'm new to this and have the same problem, can you explain what commands you used.

 

[UtterDisbelief]

I'm new to this and have the same problem, can you explain what commands you used.

Hi there.

The commands are in post #4.

Just run them one at a time in Terminal