Masonry Wall with Bullnose Corner Block

I have a masonry opening with a bullnose corner block. I need to expand the width of the hole by 1.25 inches to fit a standard door frame width. Note the end with the bullnose corner has a thicker wall. The additional wall thickness is essentially the same as the other end with the notch filled in. That notch is in excess of 1.25/2=5/8 inch. Thus the masonry opening can be expanded by the requisite amount.

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