Acer chromebase ca24v2 black screen after firmware flash

Hi, I have an acer chromebase ca24v2 (Board name: Karma) that I am trying to convert over to Windows. I flashed the firmware following the instructions on MrChromebox’s website.
After rebooting I got a black screen no backlight, fortunately I have a backup of the original firmware which I flashed with an eprom programmer. The device is back to normal.
Can anyone help me with this issue? Thanks a lot.