Hi there! I was able to load Circuitpython 5.3.0 on the PyboardV1_1 which previously had Micropython.
I used the instructions for the Feather Express with the STM32F405, which is similar to the Pyboard V1.1:
https://learn.adafruit.com/adafruit-stm32f405-feather-express/dfu-bootloader-detailsThis is what I did.
First, download the binary file for Circuitpython:
https://circuitpython.org/board/pyboard_v11/Then download the STM32CubeProgrammer software for programming the Pyboard and install:
https://www.st.com/en/development-tools/stm32cubeprog.htmlI then found the 3v3 and Boot pins which are beside each other (lower left corner, second row up if usb pointed up) and jumpered them, powered up the Pyboard using a USB cable with a Windows computer, and followed the instructions for STM32CubeProgrammer as detailed for the Feather.
The jumper placement is shown on page 6 in this guide:
https://micropython.org/resources/Micro-Python-Windows-setup.pdfor:
I am now running 'Adafruit CircuitPython 5.3.0 on 2020-04-29; PyboardV1_1 with STM32F405RG' as per PuTTy.
I hope this helps!
Mike.