Question about mem parameter in the bootargs

Hi,

Does someone knows what is the smallest step to increase the mem
parameter in the bootargs?

I am running linux in an embedded system where I have a very critical
memory constraint and  I would like to have mem=3584k instead mem=3M or
mem=4M.

The Linux boot up sucessfull with mem=3M or mem=4M but the kernel
crashes with mem=3584k.

thank you

Moratelli