USART1 ST bootloader not working on Nucleo F070RB

[Trev]

USART1 works as expected from firmware loaded via SWD. However the ST bootloader does not work. It never responds to the initial 0x7F with anything. I have scoped tx and rx and cannot see anything wrong and, as stated above, the UART works under the same conditions when running from application code. BOOT0 (and BOOT1) is being exercised correctly (I've being using the ST bootloader successfully on dozens of projects for over 10 years now). I' pretty sure this is the same issue as described here:

https://community.st.com/s/question/0D50X00009XkeL4SAJ/start-usart-bootloader-on-stm32f070-device-does-not-work

So it seems it might be a old rev of silicone (used on the Nucleo F070RB) issue. I.e a rev 447 silicone issue. Can anyone confirm this and ideally advise what rev of silicone this may have been fixed in? My customer is keen to commit to a PCB but I need to be sure this works as SWD will not be available on the end device due to using a limited pin device.

Any help appreciated.

[TDK]

Does it respond on USART2?

Chips are silicon. Silicone is something else.

[Trev]

Just to update on this. I fitted a rev 740 chip (STM32F070RBT6) to the Nucleo board and the ST UART bootloader works as expected (USART1). So it looks like it was a rev 447 silicon issue all along.