Well I have a cheap E-bay Asian nano board and using either my USBtiny or USBasp programmer was able to select the board type as standard Uno, select programmer, and finally then burn bootloader. It takes the bootloader with no problems and after that I simply use it by simply selecting the board type as Uno to perform normal serial uploading. I had no need, nor see a need to add a new board type in the boards.txt file.