I recently bought a very cheap Arduino nano clone off of eBay. I was having an issue where my computer would recognize the Arduino, I could watch the serial connection using the serial monitor(It had an ASCII printing program on it from the factory), but I couldn’t flash it with a new program.
I tried all the different CPU settings in the Arduino IDE. After many hours of Googling I found an article that explained I needed to install the official driver for the CH340 rather than the default driver included with Linux.
So I found the proper driver in the AUR, ch34x-dkms-git. Just another reason to love Arch Linux. Installed it and rebooted. I then got the knock off to work by using the old bootloader setting in the CPU options. Moral of the story: try to find the most standard Arduino you can, if you find other information in the title let it be on eBay.