Can't boot without USB on legacy system

Hi, i just successfully installed High Sierra on my old Core 2 Duo PC, everything is working good, unless for Audio And Ethernet. I can't seem to make the PC boot from my hard drive, even with EFI folder copied to the SSD's EFI partition (have BootInstall.command installed DuetPkg as well). But the system refuse to boot on the Hard Drive and just shows a blinking underscore instead. please help!

Specs: Asus P5G41T -M LX Intel Core 2 Duo E8400 3ghz 4GB 1333 DDR3 RAM NVIDIA GeForce GT 705 1024MB VERICO SSD 120GB.

submitted by /u/KhanhDoan9983
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