Given a partition size and start address, this will edit the image passed as parameter
to create a partition entry. This assumes the disk is always bigger than 8Gb while setting
the CHS address. From osdev wiki:

"For drives smaller than 8GB, the LBA fields and the CHS fields must "match"
 when the values are converted into the other format.  For drives bigger than
 8GB, generally the CHS fields are set to Cylinder = 1023, Head = 254 or 255,
 Sector = 63 -- which is considered an invalid setting."