The undecidability of basic decision problems for general FIFO machines such as reachability and unboundedness is well-known. In this paper. we provide an underapproximation for the general model by considering only runs that are input-bounded (i. e. https://www.nacrack.com/mega-pick-As-for-Me-and-My-House-Wall-Decal-in-Hebrew-Yahauh-flash-find/