The book of words that Trump has eaten is very brief. Admitting he was wrong, or just being a blowhard, is not easy for him to do. He will have to show some actual humility, not something he is likely to do.
Just look at his initial response. He gave a speech attacking the decision and the “Obama judge” who issued it. He puffed out his buffoonery to his adoring personality cult, declaring that he might just go back to the original ban that he liked better. And so on. It was more of the stupid stuff that gave the judge the ammunition for this decision. It was all the kind of things I would have told him to not say if I was his attorney.