Just mount this Real Time Clock Shield on the GPIO port of the ODROID to keep the time when your ODROID is offline. A Lithium-coin battery can keep the RTC chip running up to 5~6 years without external power supply.
1x CR2032 included, replaceable
OS Requirements
Linux: Add the PCF8563 RTC driver
Android: Update the OS release version 1.4 or latest one
Shield for the ODROID-C2 / ODROID-C4. You can still use ODROID official case using this shield.