The stock firmware had basic thermal protection. The new update implements a more aggressive algorithm. If your thermistor reports a sudden temperature drop (common if a silicone sock falls off or a part cooling fan blows directly on the nozzle), the printer now halts instantly rather than trying to "catch up." Fewer fried PTFE tubes and no burnt wiring hazards.
: Custom Marlin builds (like those found on Printables ) enable: sunlu t3 firmware update better