STM32G031Jx SO8N embedded uart bootloader

[yo3hcv]

Hello,

I plan to use STM32G031Jx in a SO8N package and use embedded bootloader over UART.

According AN2606, both USART1 and 2 can be used

But PA3 is not available on SO8N, so remains only USART1.

But USART1 is used by bootloader on PA9,10 which are not directly available on SO8N packages.
These pins become available after remap (SYSCFG_CFGR1) which is default 0.

Also in AN2606 says that

So question, how this is working?
These devices comes (blanks) having remapping activated from SYSCFG_CFGR1?

It means that PA11,12 cannot be used anymore, because if I remap them, I will not be able to enter to bootloader at next reset, right?

Thanks for clarifications,

[TDK]

It means the bootloader is remapping PA11/PA12 to PA9/PA10 when the bootloader starts up. Unlike option bytes, these settings are volatile and are cleared on reset or power-on, so the change must be done after that. Changing them in the application won't affect how this works. Once you jump to the bootloader, it takes over.