STM32WB55 boot mode issue

[DHunt.2]

Hello!

There is a board with 2 MCUs, one of them is STM32WB55, second is STM32L4Q5. I need to launch both in boot mode and load firmware over UART. When L4Q5 is in boot mode and UART1 is configured (as mentioned in AN2606) I upload firmware in this MCU and everything is going well.

I repeat the same steps with WB55. After I send start frame to WB ( START_FRAME[2] = {0x7F, 0x80};) I get ACK (0x79), but whatever I send next - there aren't ACK, only NACKs (0x1F).

What I'm doing wrong?

Best regards,

Den

[Remy ISSALYS]

Hello,

Could you check the RDP level?

Best Regards