No, but it is simpler than that. Once you have the bootloader, you use the GCS, but since you don't have firmware on it yet, you must use the manual method. Unplug all FC power (usb and battery). Go to Firmware page and press Rescue, THEN plug in FC. Then you can Upgrade, Upgrade & Erase, Open/Flash, Erase...
Make sure you do something that eventually includes Erase after flashing the firmware.