... but it won't display as manual mode.The hinges deserve some oil from time to time, but it's the switch's plunger you should clean.
I don't know if it's displayed as manual mode, but a sticking switch will keep it in first gear.
I can think of only two possible scenarios where it will display 1 on startup.
A. Fluid/corrosion in the manual switch causing it to short out.
B. a dying Primary Pulley Position Sensor (which will most likely display other CVT related symptoms as well.
I'd check for A. first.