This Could be Easier RP2040 boot sequence (RP2040 datasheet, Fig. 15). With an STM32 project, there are a few items required to make a bare-metal project work on a target MCU.

Compliant with the USB TCPCi specification, and designed to manage a separate single- or multi-port TCPC chip, ST’s X-CUBE-USB-PD stack implements the protocol layer and policy engine of the USB Power ...

[The Backwoods Engineer] tested out a new accessory kit for the STM32-F4 Discovery board. The image above shows two boards communicating with the UDP protocol. Notice the extra PCB into which each … ...