Hi guys! I got a similar problem too with reaching the installation menu.
As I couldn't boot with Clover (didn't work don't ask me why, it just froze with a non-blinking underscore in the top left conrner, but whatever), I tried with Chameleon and it worked just fine, although i still cannot access the installation GUI and stuff. I'm stuck with a couple of errors such as "DSMOS has arrived" and a couple of other things (see the last 5-10 lines of the screenshot but please don't take in consideration the "unable to enumerate usb device" error-type that was really seldom).
I'm aware it should be somewhat dealing with my GPU but, I have already checked out the manipulations in the first post (stuff like moving .kext into backup folder etc...) but it didn't work. Same thing with flags : i have already tested -v -x GraphicsEnabler=No KernelCache=No but it wasn't really effective huh. My PC is a PACKARD BELL BV IMEDIA J9610 with a PACKARD BELL BV GA-T671MG mobo (I know, that's antiquity stuff), with an Intel Core 2 Duo, and 3GB of RAM, my GPU -if you could ever call it that way- is an AMD ATi MSI Radeon R5450 in PCIExpress (and I had already turned it back to "PCI" in my BIOS).
If someone could help pleaaaase x).