How can you write a program that updates itself for an STM32, eg. for an STM32F103C8?
I'm not talking about a bootloader, since (as far as I know), a bootloader lives from (say) 0x08000000 to 0x08001000 in Flash and then updates another program (another part of flash), in this case, eg., starting at 0x08001000.
One option I thought of would be to run the code not from flash but from RAM/SRAM, like in this question and then update the flash memory, reset, and boot from flash. However, the answers there involve booting from SRAM, which I think I may not want to do. (One of the reasons being that this must run in production, without a debugger.)
Rather, what makes more sense to me is to flash the program to the STM32 flash, as usual, at 0x08000000, run the code from flash, and then, at runtime, upon receiving the update command from the user, move the entire program (or perhaps just the strictly necessary parts) to RAM/SRAM, continue execution from SRAM, and then update the entire flash memory and reset the MCU and boot from flash, again, as usual. (In particular, you never boot from SRAM, and you only run code from SRAM when you want to update.)
So, can this (or something logically similar) be done, in order to have a program that updates itself completely?
Now, I know this is possible if you only want to update a subset of flash memory (eg. I think VIA does a partial update of flash memory at runtime in order to update keyboard mappings without reflashing the keyboard and without as much as reconnecting your keyboard), but I wonder how it can be done if you want to update the entire contents of flash memory.
