Marks the image with the given image index as bootable.
BOOL WINAPI WIMSetBootImage( HANDLE hWim, DWORD dwImageIndex );
[in] A handle to a Windows image (.wim) file returned by the WIMCreateFile function.
[in] The one-based index of the image to load. An image file can store multiple images.
If the function succeeds, then the return value is nonzero.
If the function fails, then the return value is zero. To obtain extended error information, call the GetLastError function.
If the input value for the dwImageIndex is zero, then none of the images in the .wim file are marked for boot. At any time, only one image in a .wim file can be set to be bootable.