I am working on the project with STM32F030R8T6. So far I have bootloader and main application with memory space allocated. My problem is that currently I am jumping between main and bootleader using address of reset handler and I need to somehow let BL know if it is startup or jump from main. I have been trying to allocate 4 bytes to store this information in memory and access using the address, but it seems that value at the address get reset after jump. My question is — what would be the best approach to have some flag between BL and Main application ?