Thanks a lot. This is how I did the upgrade. Please anyone feel free to share your thoughts on how to either more easily or more safely do the upgrade. Of course 4k would be great still. But my family would hate me if I brick my BRIX and I don't have a Windows for creating the Firmware patch with more VideoRAM anyway.
How to upgrade new OS X 10.10 patches
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This is is how I install OS X upgrades on my BRIX GB-BXi7-4770R.
Because this computer is used by my whole family, I did not experiment with enabling 4K monitor output. My BRIX runs with the OOTB available 2560x1440.
1. Open Clover Configurator and save a copy of the currently working config.plist.
2. Update Clover Configurator via in app update dialog.
3. Update Clover. I kept all defaults when installing the new version.
URL:
http://sourceforge.net/projects/cloverefiboot/
4. Open Clover Configurator to verify whether the current config.plist was not destroyed by the upgrades.
5. Reboot via updated Clover to check that after upgrading Clover all still works well.
6. Download and install latest OS patches via Apple App Store. This results in a reboot of the OS.
7. After the OS is started and the installation was finished.
8. Starting Trim Enabler will patch the OS for using Trim for the non-Apple SSD and disable kernel extension security checks.
URL:
https://www.cindori.org/software/trimenabler/
9. Opening System Settings/Audio will show that only HDMI sound is supported.
10. Patching the current Audio driver on board of the BRIX:
URL:
https://github.com/toleda/audio_CloverALC
Download latest: audio_cloverALC-100.command.zip (as of today)
Unzip to file: audio_cloverALC-100_v1.0.4d.command (as of today)
Execute: $ audio_cloverALC-100_v1.0.4d.command
Answer the following questions as shown.
Password: <admin user password>
Confirm Realtek ALC269 (y/n): y
Clover Audio ID Injection (y/n): y
Use Audio ID: 1 (y/n): y
11. Reboot.
12. Check sound is working by selecting it under System Settings and playing some sounds.