There is no official firmware with save state support atm, there is a version of save states in an older OG SD2SNES firmware that works but doesn't capture the state of the APU so you can have issues if the game was relying on data going through there for certain things. They've said they may re-implement the APU on the SD2SNES Pro, allowing it to overtake the SNES and thus capture the state of the APU for a full save state save/load, not sure the OG cart will be strong enough. Also Kevtris has said that the SuperNT will always win over the SD2SNES in that scenario, so it will not work on that system.