If you want to boot the ODROID-C2 via OTG port, please use a 5V/2A adapter.
OTG booting is unstable in some environments.
Most features are described here.

This page describes the proper use of the OTG port.

OTG Booting

The ODROID-C2 can be powered not only by DC jack, but also OTG port.
Before using an OTG port, you need to check your ODROID-C2 header pin J1.

When you want to power the ODROID-C2 via the OTG port, the J1 jumper must be plugged in as shown above .
If the J1 jumper is not connected, the OTG port cannot be used for the power input.

OTG port & DC jack

But when you connect the ODROID-C2 to the DC jack and the OTG port together, and ODROID-C2 is powered via DC jack and you must REMOVE the J1 jumper!
Otherwise, your C2 board can be damaged.

You must disconnect the J1 jumper as shown in image above.