External display stops working since 10.10.3

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Press option when you select "Scaled".

Thanks a lot.
When i did that, it gave me:
1600x900
1344x756
1280x720
1024x768
800x600

There is no scale option of 1920x1080.

Below i attached my config.plist, hopefully it has some useful information.
View attachment config.plist

 

[RehabMan]

Thanks a lot.
When i did that, it gave me:
1600x900
1344x756
1280x720
1024x768
800x600

There is no scale option of 1920x1080.

Below i attached my config.plist, hopefully it has some useful information.
View attachment 134883

Regenerate config.plist with latest PBI-CE (yours looks old).

 

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Regenerate config.plist with latest PBI-CE (yours looks old).

I have tried the below ways, but failed to regenerate config.plist (using latest PBI-CE)

1. Keep original config.plist file, and run the PBI-CE (not check "Don't generate config.plist" in options), after PBI finished, seems config.plist hasn't been touched (from the file modified date)

2. Remove the original config.plist from its path, run the PBI-CE, after finished, no new config.plist file created.

3. Boot from USB, in recover mode, did the above again, same result.

I have also update the 'Clover Configurator', and use it to generate the config.plist, but seems that file won't work on 8470p.

 

[RehabMan]

I have tried the below ways, but failed to regenerate config.plist (using latest PBI-CE)

1. Keep original config.plist file, and run the PBI-CE (not check "Don't generate config.plist" in options), after PBI finished, seems config.plist hasn't been touched (from the file modified date)

2. Remove the original config.plist from its path, run the PBI-CE, after finished, no new config.plist file created.

3. Boot from USB, in recover mode, did the above again, same result.

I have also update the 'Clover Configurator', and use it to generate the config.plist, but seems that file won't work on 8470p.

You're probably running PBI-CE with the incorrect options. Make sure you follow the guide: http://www.tonymacx86.com/hp-proboo...-install-yosemite-hp-laptops-clover-uefi.html

 

[bulkonly]

You're probably running PBI-CE with the incorrect options. Make sure you follow the guide: http://www.tonymacx86.com/hp-proboo...-install-yosemite-hp-laptops-clover-uefi.html

Thanks for reminding this.
I have fix the problem by re-installing the Yosemite.

The reason:
I have 2 sets HP8470p, a low screen resolution, and a high resolution; other configurations are same between the 2 8470p.
I selected the low resolution 'config.plists' file to make the 10.10.0 boot USB, installed for the low resolution one, works good;
then i use the same USB key to install the 10.10.0 for the high resolution, it worked good as well. When i upgrade to 10.10.3, the high resolution one's HDMI works abnormally.

Finally, i re-made the USB by a high resolution config.plists. it works.Thanks again for the help.