C is a connector type that allows macOS to handle both DisplayPort and HDMI, very useful for example on some ThinkPads when a USB C (DP) and an HDMI are wired to the same pipe.
In hex, C is 8+4, 8 being type HDMI and 4 being DisplayPort.
Unfortunately, when injecting that property (framebuffer-conX-type 000C0000), Hackintool doesn't know how to deal with it, so it'll just crash when going into Patch -> Connectors
I was able to recreate this issue on two different machines already.
Would it be possible to add support for this connector type, or at least prevent the app from crashing?