Note that my discussion in the prior posting is focused on boot loader implementation that embeds itself in the standard architecture and programming module for the MCU. But keep in mind that there are often other hardware mechanisms designed into various MCUs that may lend themselves to boot loader implementations that follow other schemes with respect to the use of interrupts and the interrupt vector table. Here is a short list of some of the things you may encounter:

1) Relocatable interrupt vector table that has its base address programmable in a hardware register. It starts at a default location but may be moved to other places in the code memory.

2) Implementations with two interrupt vector tables with one intended for the application and one for a boot loader.

3) Implementations with dual flash pages mapped to both include the the reset start up point. One page for application and the other for the boot loader. Setting of the page selection is based upon the means used to invoke the boot loader and will be system MCU specific.

There are other things I've seen dreamed up by various MCU makers over the years.

Michael Karas