How to use USB-DFU in presence of UART or I2C or SPI being present in the code running on the board?

[SSoni]

I was using USB-DFU for uploading LED related codes on STM32F446RE but then I came across bootloader selection flowchart which I am attaching with this question. According to this flowchart, I won't be able to access the bootloader mode in presence of protocol which at a higher priority in the flowchart so I tried accessing bootloader via USB when a code using UART was present on the board.

I am not able to access the bootloader through USB now.

Kindly suggest a way for accessing the bootloader through USB in presence of UART or I2C or SPI etc in the already running code which come above in the bootloader access priority list.

Thanks in advance

Siddharth

[SSoni]

Kindly help guys!

[SSoni]

Guys, is the question not clear? It is really urgent.