Hi Micheal

The only time I used a banked system on the 8052 was with the IAR EW8051 C Compiler..

The IAR has many limitation's when banking.It would only generate banked addresses for function calls,All C runtime library functions,interrupt routines,variable intitialisers, and the Cstartup code had to be in the root bank.
This meant that if the root code was say 10k, then the lower 10k of all banks was inaccessible.

For debugging we always broke the code down into small working modules that would fit into the 64k.Once they were ok,we banked them and retested.And I cant recall any real problems.