-m8k
This option instructs the linker to generate code for parts with no more than 8K of code memory. In particular, the linker will always use RJMP instructions for relative branches which can wrap around the 8K memory space. Even if you are using less than 8K of memory for your application on devices with more than 8K of memory, you should still not use this switch as your application will fail.
To use the hardware multiplier for a project:
It is not possible to set the Flash Size property on a per-file basis.
-m128k (Generate for 128K part) and -m8m (Generate for 8M part)