Congruence-simple multiplicatively idempotent semirings

Let S be a multiplicatively idempotent congruence-simple semiring. We show that $$|S|=2$$ if has absorbing element. also prove is finite then either or $$S\cong {{\,\textrm{End}\,}}(L)$$ $$S^{op}\cong where L the 2-element semilattice. It seems to an open question, whether can infinite at all.