Kindly advise what Bracha Reshonoh to make on A) instant oatmeal which comes packaged made of whole grain rolled oats (with oat bran) oat flour and you pour half a cup hot water over it, or B) you pour half a cup cold water over it and place it in microwave.

Assuming that this appears the way most oatmeal does, it is mezonos regardless which way you prepare it