Can't install Win 8 from internal partition

Hello! Back story: With Windows 7 Using legacy bios settings I was able to use EasyBCD to add another entry to the boot menu, referring to the boot.wim file of a copied ISO image to another partition of an internal hard-drive. This allowed me to install Windows 7 from another partition and with an SSD drive I could get it installed in two minutes; however, when the bios settings was set to...