So there are three reset procedures, which the SD on my YYZ-HND flight tried in sequence:
- Reset from the flight attendant panel
- Reset using the touch-screen seat controls (using the password sequence noted above)
- Reset using a switch under the seat
In my case, steps 1 and 2 did nothing, and step 3 did temporarily fully re-inflate the seat. About an hour later it had deflated about 50%, and repeating step 3 fully reinflated it again. I then moved seats.
Luckily for my HND-YYZ yesterday my seat stayed inflated.