We designed a PCB with stm32f030c8t6. We soldered the PCB and tried to upload the code. Power has gone to the stm32f030c8t6 successfully but when we arranged a pin as a gpio output it wasn't high.
As you see to your target there are many Infos existing at Keil. Another one is our "Application Note 286":
https://www.keil.com/appnotes/docs/apnt_286.asp
I hope with all these links you manage to approach a solution, good luck!