Should it work if I go to open firmware and type boot usb0/disk@1:3,\System\Library\CoreServices\BootX because that works with normal installersGenerally there are two ways now: Either fetch the Installer (for A96 or A190) and modify them as described on the first page(s) or get the pre-patched Installer for i.e. A96 (only server build, at the moment). When cloning either of them back to your install volume (that you´d attach to the target system via Firewire or USB (not possible to boot on older Macs from USB!) you´ll have to make sure that you set that checkmark in disk utilities, otherwise boot might fail in many cases.