Nope the Futuh doesnβt say that only Castanhosa says thatNo this was the banner of Sultan Sabr ad-din I believe - - - - or was used early on by the Imam.
Several red banners was used in Adal. Including plain red in Aussa.
But in the Futuh it says that Imam took two white banners and one red banner together with the crescents. This is simply a modern interpretation of what is said on the Futuh and it looks bad ass so might as well make it official.
This is what the Futuh says