HS only boots from USB. HELP!

Hello guys, I'm a little desperate, I spent way too many days/hours trying to make 'Bella' work but no luck.

Z68X-UD3H-B3

i7 2600k

GTX 570

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So OS X is installed but I can't boot from my system drive. It only boots through the USB. I searched and tried a lot of things but the issue remains. What I tried:
- replacing EFI partition from USB to my drive

- change boot drive to my drive's name in config.plist

- updated my bios to UEFI

- messed around with BIOS options

- reinstalled HS 5-6 times.

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*Funny/weird thing is that in the beginning it worked! Booted fine! but then something was wrong with my mac account so I decided to reinstall. And then the issue came up. Also in the very first install it seemed like NVIDIA drivers were working fine but after I reinstalled they don't seem to work anymore. Makes me thing if something goes wrong with Multibeast.

**I am using Legacy in clover but now I updated my BIOS to UEFI. Could this be an issue ? My motherboard is a 6 series.

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Any help would be appreciated. Thank you.