The following are two options you may use to flash the firmware HEX file to the Arduino nano board.
The CH340 chip is used by a number of Arduino compatible boards to provide USB connectivity. You may need to install the following driver to connect and flash firmware to these boards.
Using avrdude to flash the HEX file to the Arduino Nano board.
avrdude -U flash:w:[HEX FILE]:i -e -p atmega328p -b 57600 -c arduino -P [COM PORT]
Example:
$ avrdude -U flash:w:pidflight-lap-firmware-1.2.0.hex:i -e -p atmega328p -b 57600 -c arduino -P /dev/ttyUSB0 avrdude: AVR device initialized and ready to accept instructions Reading | ################################################## | 100% 0.00s avrdude: Device signature = 0x1e950f (probably m328p) avrdude: erasing chip avrdude: reading input file "pidflight-lap-firmware-1.2.0.hex" avrdude: writing flash (7350 bytes): Writing | ################################################## | 100% 2.26s avrdude: 7350 bytes of flash written avrdude: verifying flash memory against pidflight-lap-firmware-1.2.0.hex: avrdude: load data flash data from input file pidflight-lap-firmware-1.2.0.hex: avrdude: input file pidflight-lap-firmware-1.2.0.hex contains 7350 bytes avrdude: reading on-chip flash data: Reading | ################################################## | 100% 1.73s avrdude: verifying ... avrdude: 7350 bytes of flash verified avrdude: safemode: Fuses OK (E:00, H:00, L:00) avrdude done. Thank you.