EFR32MG12P VectorTable relocation issue

I am using EFR32MG12P controller to update the firmware from external flash and I am storing new application in the internal flash at 0x40000 address. After updated the new firmware I used mbed_start_application(0x40000) function to reboot to the new application but my bootloader is not responding and it’s not executing the new application. So, I suspected it’s because of the vector table and I tried to relocate vector table forcibly from 0x00 to new application address but still vector table located at 0x00 not at 0x40000.
Even I tested application without bootloader like, I just took the blinky example code and changed the MBED_APP_START address from 0x00 to 0x800 and tested the application. Even in this situation also program doesn’t respond with any output. I am not sure what is going wrong, I am still thinking its because of vectortable can’t relocate with the application. I looked at so many blogs about relocating the vector table but didn’t help much, Could you please help me with this situation and suggest me if I am missing anything.

Thanks