We study the problem Gathering for n autonomous mobile robots in semi-synchronous settings with a persistent memory called light. It is well known that Gathering is impossible in the basic model (OBLOT) where robots have no lights, even if the system is semi-synchronous (called SSYNCH). Gathering becomes possible, however, if each robot has a light of some type that can be set to a constant number of colors. In the FCOM model, the robots can only see the lights of other robots. In the FSTA model, each robot can only observe its own light. In the LUMI model, all robots can see all lights. This paper focuses on FSTA robots with 2-colored lights in synchronous settings. We show that 2-color FSTA and FCOM robots cannot solve Gathering in SSYNCH without additional assumptions, even with rigid movement and agreement on chirality. We also show a Gathering algorithm for FSTA robots with 2-color SSYNCH with minimal additional assumptions. © 2026 The Author(s)