Thank you for perfect guide. I tried XPC in 10.6, 10.7 and dual boot with Win7. All worked perfectly. But I still can't install XPC on HDD. After pressing Shift+I in boot menu, it say at first "Efildgpt copy error. Not found" and then "Boot is patched successfully". Efildgpt lay on both XPC partitions at USB stick and EFI partition. Does anybody have some ideas about subj?