The first flag of Northern Ireland? But was the Red Hand actually Green?

Possibly. Graphic from this description of the Ulster Pavilion at the British Empire Exhibition of 1924. Perhaps archival photographs exist somewhere. Further details online here.

The one-time shipyard worker William Grant, by this time the MP for North Belfast, was not impressed –

"I would like to ask the hon. Member a further question. Is he aware that a great deal of dissatisfaction exists amongst those who have visited the Exhibition at the Ulster Pavilion, that the only persons who appear to be satisfied with the Exhibition are the Ministry themselves, and that those who ought to be satisfied are a great deal dissatisfied? ... Is it a fact that the decorations of the Ulster Pavilion are green, yellow and red, and that at the opening of the Exhibition the red hand of Ulster was actually painted green? As the answers given are so unsatisfactory, I think we should raise this matter on the adjournment of the House."

So what should have been Northern Ireland's greatest showpiece event turns into a farce. Controversy and not celebration. A self-congratulatory government department making a horlicks of culture?....