Hello @koreanEggCoffee yes, that is possible - I am powering my M5Atom this way. However please note: There is no protection against wrong polarity so please be careful not to accidentally swapping 5 volts and GND. I also suggest you disconnect the external 5 volts before connecting USB-C. Or in other words only connect one power source at the same time. Please also refer to the M5Atom schematics which outlines the 5 volts connections between USB, 5v pin, Groove, LEDs and 3.3 volts regulator. https://docs.m5stack.com/#/en/core/atom_matrix Cheers Felix