Powerup the Linkit one

hi

on arduino boards there are a VIN pin for external Power

is there a way to powerup my linkit one without the usb

i try to connect my arduino mega to linkit one the power from arduino comme from accu go to VIN
i connect :
5V arduino to Linkit one 5V
3.3V arduino to Linkit one 3.3V
GND arduino to Linkit one GND

but on the linkit one i have only Power outputs

There are two ways to power up a LinkIt ONE, USB or Li battery.
Actually VIN is connect to nowhere in LinkIt.
As for 3V and 3.3V, it’s just output, and it wound not generate 3.7V that 2502A core need.