The PWR_BTN# pin is not required to power ON the OSM. PWR_BTN# is used to switch ON/OFF the i.MX 8Xlite CPU and is connected to a push button switch in the carrier board.
PWR_BTN# Switch:
Shutdown: Long press, the i.MX 8Xlite CPU will shut down.
Turn ON: Short press of the same button will turn ON the CPU.
if the PWR_BTN# pin is left unconnected the OSM will automatically boot by default when power is initially applied.
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G46M product information in the below link,