Moreover, I've another question: does my installed chameleon (and its settings) influence in any way the boot using Clover from USB?
If you're booting from the USB your clover installation on your HDD will have no effect.
The rebooting issue seems especially odd, If you're getting a black screen after applying the Shrike patch, this is good. It (probably) means it's loading the patch, but you've got the wrong values.
I'm pretty confident we'll get there with your setup as it's very similar to mine, however, I've got no experience with this on Mountain Lion, only Mavericks. It took an awful lot of time however! I'd personally recommend doing a clean install with Mavericks because it seems faster than ML - but that may not be possible if you're using old kexts to get your system running.
To get the values right you'll be doing a lot of rebooting and trial and error, I used clover to apply the patch making this easier, and reduces the possibility of error with kext permissions and whatnot:
^ I put this inside <key>KernelAndKextPatches</key>, it searches ATI4600Controller.kext for the string in ATIConnectorsData and replaces it with the string in ATIConnectorsPatch. The ATIConnectorsData string is the unmodified Shrike framebuffer personality Alex gave you.
(make sure you reset to the vanilla kexts! It's important that you can find the ATIConnectorsData Shrike string in ATI4600Controller)
It's worth learning how you create your own framebuffer personality, it's actually relatively simple when you get into it and will make it much easier when you're trying to figure out which numbers to change! This post explains things pretty well http://www.insanelym...n/#entry1655182
So a port configuration, like for LVDS, breaks down like this:
(CCCCCCCC) Contector Type
CCCCCCCC AAAAAAAA FFFF ???? TT EE HH SS
Most of these we can be sure of, we're only really interested in changing SS, EE, maybe TT and the last two of features, --FF
The post I linked roughly explains how to find these values, but I had to do a lot of searching on the forums. Mine should look pretty similar, for LVDS it's
02000000 40000000 0901 0000 12 01 00 07
and I've not changed the others. (HDMI & VGA)
Also, it's worth looking at these a lot when changing clover config.
especialy this section http://clover-wiki.z...ration/Graphics
I hope it goes well, good luck!