no A/T wakeup in that scenario- but further I think the speculation is the Asiana crew set the MCP alt to zero.
Minimum Maneuvering Speed
Indicates maneuver speed margin to stick shaker or low speed buffet. Top of the bar is the airspeed that provides:
1.3g maneuver capability to stick shaker with flaps down
EICAS message AIRSPEED LOW
Level: Caution
Aural: Beeper
Message Logic: Airspeed is below Minimum Maneuvering Speed
The autothrottle can support stall protection if armed and not activated. If speed decreases to near stick shaker activation, the autothrottle automatically activates in the appropriate mode (SPD or THR REF) and advances thrust to maintain minimum maneuvering speed (approximately the top of the amber band) or the speed set in the mode control panel speed window, whichever is greater.
Note: When the pitch mode is FLCH or TOGA, or the airplane is below 400 feet above the airport
on takeoff, or below 100 feet radio altitude
on approach, the autothrottle will not automatically activate.
The A/T ARM Switches looks like they were in OFF. Or the airplane went below Minimum Maneuvering Speed below 100 ft RA. But still AIRSPEED LOW + beeper + Caution at 100ft RA ...