Attempt a standard software update via USB first.
If the USB method fails, the eMMC chip must be desoldered and flashed with the firmware image (User and ExtCSD partitions) using a programmer. Official Resources Download 35019017 1920x1080 DNS 42AK9000 part1 rar
KPS-L090C2 (utilizing TEA1733 and 4N60L chips). Flashing & Recovery Process Attempt a standard software update via USB first