FPGA image in flash/boot copier

Both the 'flash' boot code and the JTAG download work by running code on the nios cpu (from a block of internal memory) that writes copies the data into the required instruction space.

However, even if you aren't using the nios cpu to load the code, you may need data access to the instruction memory.

The program '.text' section probably contains readonly data - look at the symbol table and/or request the linker generate a map file.

The other fubar is the jump tables used for C switch statements, with gcc4 (as built by Altera) these are forced into the .code section - and there is nothing you can to do change this without rebuilding the compiler.