?nios2-elf-objcopy used to create

When I locate the code and data segment in the same memery device,eg. sdram, i can create the binary file what i want whit command line '$(OC) --output-target=binary $(PRJ_NAME).elf $(PRJ_NAME).bin'. But, when locate in different memery device, such as sdram & flash, i get the binary file which includes two memery range data!

I don't get the real command to set the starting address & the ending address! How can i do it? Please, thanks!