Z68-UD3H-b3

I have a really old Hackintosh, which is my first and only, and it desperately needs to be updated.

It is currently at 10.7.5 and is running f12 BIOS. I've attempted to update the BIOS to UEFI with @BIOS and it gives me the error "cann't get "Bios.ini" file in selected @BIOS server" (yes, can't is misspelled in the error)

I've also tried updating from QFlash with the F12 update.

Am I using the correct file? Or should I have downloaded U1n(UEFI BIOS) Download page here

Is it necessary to update the BIOS to update 10.7.5 to Sierra? Or do I scrap the entire thing and build new?

I don't have an identical MB as you do but the Z68MX-UD3... and I'm able to run at least 10.10 Yosemite without UEFI. Currently runs F13 bios I think. I'm also searching for clues whether our old systems are able to run the latest 10.12 Sierra but without any success so far. I've followed the official universal Unibeast (with Clover boot loader) guide for Sierra but gets major red text crash right at startup/boot sequence.