Hey everyone,
I got it to work (Thanks a lot everyone who created, who tested, etc ), with a few weird hiccups, so here i will document how i got it to work, in case anyone has the same problem(s).
NOTE: Please tell me if anything i type is wrong or should be removed, i registered specifically for this one thing.
Okay, so in short, everything works fine as far as what i have done so far (including updating to the 6th update, which is currently the newest DSM version).
But here's the deal, it wasnt just follow the toturial and boom, done... No, instead, i had to first get the usb drive to be bootable (jun's img file woudnt boot for some reason.
so what i did whas this: i used win32diskimager to write "jun-baremetal-hybrid-uefibios-arcao-v2.img" to the usb drive... BUT, after that, i just copied the contents from "synoboot.img" and pressed "overwrite files". That's how i got it bootable.
After that, it was just as the toturial says, followed the instructions and now it works.
Also, my install was a migration, and except for the PXE server i had running on 5.2, everything was succesfully migrated.
My setup is as follows:
Hardware:
-Motherboard: Intel® Desktop Board DG31PR
-CPU: Intel® Pentium® Processor E2200
-RAM: Some off-brand 2x2GB 1333mhz
-Storage: 2x 3TB WD Red running in raid 1 - btrfs
-Storage: 1x 1TB WD Black running normally - ext4
Yes i understand the above hardware is not even remotely meant for NAS use... but, That's all i had lying around.
There are some other versions of the motherboard, so here's an image of the correct one. (Found online):