OK... forget it... turns out Ubuntu has 1 MB limit on RAM extraction, as defined in the kernel.. and obviously, that's good security, because then a hacker can't extract your passwords from RAM etc...
And so... yeah.... this thread is now SOLVED
Here is the full info, for anyone interested....
Quote:
if your kernel was compiled with STRICT_DEVMEM=y (see e.g. /boot/config-KERNELVERSION) then only the first 1MB is read from /dev/mem . This isn’t so much a kernel version issue, as a result of how your own machine’s kernel was compiled; most distro kernels will have this restriction in place for good reason.
You can download and insmod the forensic kernel module fmem to work around this; at your own risk! rmmod it as soon as possible afterwards. The fmem module provides a /dev/fmem device without any security restrictions.