Well since you already have 1.5 the update in firmware is just a simple download. So it takes no time at all to do, but whatever floats your boat
I didn't realize that your on stg 1, then yes 1.2 is the most resent map.
If your still having a stall problem, load the STX map as your base and the regular Stg 1 93 map as your realitme
Try it out and see what happens, but 1.2 should have the fix