I had a hard time the last days struggling with STM32G07 bootloader.
Finally I came to this conclusion:
I have option bit nBOOT_SEL cleared (unckecked in STCubePorgrammer) and even though this bit is long cleared ie several power cycles have been done since that it fails to go to bootloader with BOOT0 pin high and properly connected via UART to STCubePogrammer after a reset IF it had seen an ST-Link connection some time before reset. The only things that helped me out was a power on reset without ST-Link connection. Unfortunatelly on a NUCLEO-G070RB board it seems that pluging in USB connector establishes a short SWD connetion to the target uC thus a following BOOT0 start of the bootloader failed.
Hope this helps someone else with similiar trouble
Martin
