Andy,
Please reconsider your plan to put the re-programming code at the Bank 2 location. You should make sure that the boot loader function uses a design such that if there is a power loss during the time that update is in progress that it is easy to re-start the process over again. With the scheme that you describe you will run into a big issue if you have the flash block with the Reset and Interrupt vectors erased and then there is an upset.

Please take a close look at the postings I made here a loooong time ago for a loader that worked nicely for the 'F12x family of parts. That loader was written in assembly language so that it can share overlapped use of resources with those of the C code application with minimal special manipulation of the application code.

Here are links to threads where I've discussed boot loaders.

http://www.8052.com/forum/read/177016

Michael Karas