I've begun work on supporting the STM32G474RET6, and also the B-G474E-DPOW1 Discovery board.
So far I don't have much to show, but hopefully there will be much more in the coming days. What I have so far is in my fork, in a branch called stm32g474: https://github.com/hartmannathan/incubator-nuttx/tree/stm32g474 I'll be back with news and updates, and probably lots more questions!!! Cheers, Nathan
