Debugging hardware is hard

I've had enough bad experiences with ST to just avoid their MCUs altogether when possible. Last year I wasted several days trying to figure out why a certain ST chip wouldn't respond to the programmer I was using. The chip claimed to support flashing from UART, but the bootloader just never answered. It responded to other interfaces like ST's two wire interface, whatever it was called. Searching around online, it seems like this chip has a silicon bug or a bad ROM and ST is just happy to keep selling it as is for years. They haven't even published errata acknowledging that it's broken and doesn't answer on all interfaces.