Comment 280 for bug 930447

ERROR: PAE is disabled on this Pentium M
(PAE can potentially be enabled with kernel parameter
"forcepae" - this is unsupported, may cause unknown
problems, and will taint the kernel)
This kernel requires the following features not present on the CPU:
pae
Unable to boot - please use a kernel appropriate for your CPU

-o-

So I used the following modified lines in grub.cfg

 linux16 /boot/vmlinuz-3.13.0-14-generic root=UUID="string" ro quiet splash forcepae $vt_handoff
 initrd16 /boot/initrd.img-3.13.0-14-generic

and it boots and runs :-)

WARNING: Forcing PAE in CPU flags
...