Problem while compiling NIOSII application to be loaded into DRAM from FLASH

The error is a call instruction that needs to change the highest 4 bits of the address - probably a call from on-chip memory to SDRAM.

You can make the code work by using an indirect call.

But you probably want to have the irq entry point into the 'bootloader' and have the application register it's own function.

That means you probably don't want the code from alt_irq_handler.c in your application.