memdump is a (ridiculously simple) tool for dumping Linux I/O memory from /dev/mem, similar to devmem2. While devmem2 is excellent at reading and poking at registers, it's not capable of dumping out a whole region of memory (a Boot ROM, for example). memdump is designed for just that. It's not able to write to memory or nicely format register values like devmem2 can, though, so keep both tools handy.

Download. Run make. That's all.

Obviously, memdump will only work with kernels that have /dev/mem enabled. Although it's great for dumping out I/O memory, /dev/mem can have problems with memory that's otherwise in use by the kernel, so expect trouble if you try to use this tool to dump process memory. Newer kernels are configured by default to explicitly forbid /dev/mem from accessing process memory, and you'll get an Operation not permitted message if you try.