This is a really peculiar crash. They actually do not have data on the cockpit voice recorder for the final four minutes of the flight, because it seems that both engines were out and the plane had no power, so there was no way for the microphones in the cockpit to work. It is a total mystery how the pilots kept the plane in the air for four minutes at that altitude and why they didn't engage the APU to gain emergency power to extend the flaps and landing gear.

Via The AV Herald:

On Jan 13th 2025 South Korea’s Ministry of Transport further detailed, that the CVR stopped recording at 08:58:49L before the crew declared emergency at 08:59L. The ministry further reported that structures endangering flight safety like concrete mounds for ILS antenna will be replaced or removed. Three more airports in South Korea with such structures have been identified.