Hi
I have a problem similar to what reported by pepelu:
I use Chameleon RC5 ver 668 with a 500 GB internal hdd (GPT), Mac OS X 10.6.7, Win 7, Ubuntu on it. I have noticed that plugging in an external usb hdd (Samsung 320 Gb, also GPT) makes Chameleon stop after boot0 and cause a system restart IF (and ONLY IF) the usb disk contains more than one partition. The format (hfs+, ntfs, fat) and the size of these partition is not relevant.
Making these partitions bootable has also no effect.
If I unplug the external disk, everything is OK, I can boot snow leopard, connect the external disk and all partitions of the external usb-hdd are visible and perfectly usable.
I have an Asus eee 1000h, 2Gb RAM, Bios Rev 2204.
Thanks