Like many embedded cores, Cortex-M&#x27;s don&#x27;t have an MMU - everyone sees physical memory. In fact, I believe that&#x27;s the chief distinguishing feature of the 3 core levels - Cortex-M&#x27;s have no MMU, Cortex-A&#x27;s have memory paging, and I think Cortex-R&#x27;s are in between and have memory segments like MIPS.<p>So if the board designer wired everything up to map RAM at address 0, then yes, you&#x27;d be able to dereference a pointer to address 0.<p>Completely beside the point, though. Dereferencing NULL is always undefined behaviour in C.