Could you help me to give me some instructions how I can manage the following problem?
Background: There are some smart meters which are operating somewhere in Africa. It takes 2 to 3 days to update the firmware (using the Card reader on that meter. It is reading the firmware from a 64kb Chipcard ) on the meters. Shortly we upgraded our meters with a Xbee module. So the idea is to reduce, the three days with using the radio communication to send the firmware.
Challenge: I'm not able to rewrite the bootloader with an ISP programmer. I read that, some page(on the bootloader) is holding the sp instructions and it shouldn't be erased. How could I identify that page?
The current bootloader reads the 64Kb chip card and rewrites the application pages.
What I want to do is: Write a program which is acting as an application. So the bootloader is going to write it on the flash (application section). After that, the program will rewrite all bootloader pages. So I have a new bootloader.
The main application will be wiped out of our meter, but the bootloader will wait until the XBee gateway starts to send the current firmware.