This is the 1Bitsy STM32F415RGT6 breadboard friendly, JTAG/SWD enabled development board.
If you don't have a Black Magic Probe V2.1 JTAG/SWD programmer and debugger. We recommend getting one, it's a great complementary tool. Black Magic Probe V2.1 makes debugging and insight into the software you will be developing for your 1Bitsy very easy and straight forward. You can use the Black Magic Probe with other ARM based platforms like Discovery boards, UAV autopilots or Raspberry Pi.
Alternatively you can boot your 1Bitsy into DFU bootloader mode.
For more information please visit: http://1bitsy.org