Booting stm32mp15 series board using UART interface

[prik_29]

Hi All, I am working on board bring-up of custom board based on STM32MP157f-DK2. I am using the Starter Package provided by ST. I am able to flash SD card and boot the DK board, via USB interface, but I am facing some issue when I flash via UART interface, the CubeProgrammer software hangs and is not able to finish the flashing process.  
In our custom board which has STM32MP151fAC1 microprocessor, we have only UART interface, therefore we are not able to flash sd card with the image.
It would be really appreciative if anyone can provide me with some lead in this issue.