how u gonna maintain <1k rpm when the idling also 800 rpm already??

Guys, i drove to genting 3 days back. During downhill, when i hit the brakes, it will come out the screeching yiiii sound (occasionally). And the when on the highway, when i hit brakes again, the sound gone.

After 3 days of normal driving, i did not detect any sound during braking.

Is there anything wrong, or its just overheating??

Btw, stock pads with 4.8k mileage.