The STM8S discovery is an evaluation board for the STM8 MCU.

As with all STM evaluation boards there is lengthy list of restrictions in place regarding what you can and can't do with an evaluation board. See this document.

Install STM8Flash and SDCC.

hg clone http://hg.kewl.org/pub/miniblink-stm8s
cd miniblink-stm8s
make flash