ASROCK Z170M OC Formula Manual page 209

In this step, please particularly pay attention to the Index number in the first command.
Index represents the different versions of Windows® 7. Please check the followings for the
versions you use:
Index : 1 Windows 7 HOMEBASIC
Index : 2 Windows 7 HOMEPREMIUM
Index : 3 Windows 7 PROFESSIONAL
Index : 4 Windows 7 ULTIMATE
Step 12
Use a program that can create and modify ISO files, such as UltraISO, to copy the modified
"boot.wim" and "install.win" files to the same directory in the Windows® 7 installation disk
and cover the original files. (We recommend backing up the original version just in case.)
Save as a new ISO file, and then burn the CD or USB which can be used to install.
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