https://gist.github.com/RickKimball/71a ... 2ecf4e095/
From the readme.md
This gist provides a way to maintain a custom set of boards that work with stm32duino. Two new boards are added, 'Maple Mini Custom' and 'Blue Pill'. I wanted a stable configuration that isn't changing without me doing the changes. The default boards seem to be subject to everyone's flight of fancy. Using a boards.custom file, I know it won't change.
The maple mini board adds the ability to run without a bootloader. This give you back full access to the entire flash and ram. It also adds 3 new upload options, Serial, BMP, and STLink while retaining the pin mapping of the maple mini variant.
The Blue Pill board provides a stable configuration for a "bluepill" board that is really the stm32f1c generic variant.
To use this extract the files in this gist into ~/Arduino/hardware/STM32F1. Using the Makefile provided, a file called boards.custom is appended to the github boards.txt file after pulling the latest boards.txt from the stm32duino github repo.
# stop the Arduino IDE
$ make clean all
# start the Arduino IDE, you should see 2 new boards "Maple Mini Custom" and "Blue Pill"