Hi all i have to write an interface program for write to the stm32f40x's flash. I did a control system but users want to change some parameters on program but i can't give them the sources. I must write bootloader program and it must go on pc and controller must on read and write protect mode and i want to send go on unprotect mode (just for write) and write to flash and go again write protected mode. Is it possible or not?? I did not find any document about that. I'm looking for something about that but just find flash programming documents and i just know stm32f40x has the own bootloader.