Last block was being skipped, fix by changing the loop test from "<" to "<="
First block argument was ignored, always started from block 0 (and counted
the wrong blocks as bad if first was nonzero). Now we use it.
Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>