header.
Skipping flash after just checking a 1K header is
incorrect in the case where something scribbles over
the partition after the header because flash_image
would not be able to rewrite the whole
partition due to this check.
Also, Samsung devices use a combined boot and
recovery image where the header is the same even if the
initramfs changes and these do not get flashed even
if the boot.img is actually different due to different
appended initramfs.
Change-Id: I53ab0a23347cdf1fa7ff58dff37e812fd84645be
7e70b6be7f