I have two boards, both with the G473.
I am using the ROM bootloader on SPI1.
On one board, the bootloader works. On the other, it only responds with 0xA5 during the initialization sequence.
The MCU can program and run if I load it through the SWD port.
I have checked the SPI signals, both digital and analog, they look great. The MCU pins are firmly soldered to the board. The other board works. My code works. If you can actually get the bootloader to synchronize, it works.
I have gone through every forum post I can find, and it is sounding like there is a possible consensus that the ST bootloader is bugged and will sometimes initialize the wrong interface. Is that... really true? It selects the wrong interface and all of these people are having problems with it? Can any one from ST talk about this? This sounds like a really serious problem if true! What else could it be?
AN2606 says the G473 will init the pins on the USART and I2C interfaces to pullups - so the fact I have those unconnected shouldn't be a problem. Nothing is happening on those pins. The other SPI port's NSS is always high, so that interface can't be enabled (unless the bootloader has a bug!).
