The best cure for a flogging rooster is to get rid of him. Most of them can't be "renovated", sadly. You may make one afraid of you, but that just means he'll be sneakier next time. If he starts behavior before mating age, he's usually testing boundaries and you can sometimes nip it in the bud, but if it's later on, he may never be trustworthy. I have several very calm, even-tempered, non-human-aggressive roosters and it's a joy to have them. The ones who flogged me are no longer here.