I had a few problems recently upgrading to the latest Debian kernel as the psmouse module didn't work (simply cured by re-installing the new kernel), and I'd forgotten I'd manually installed the snd-hda-intel module, which was wiped out and I had to reinstall it.

It occurred to me I should have some way of easily booting the previous kernel and modules, but I can see no way to do this. I use LILO and have no "linux.old" entry in lilo.conf.

Can someone explain to me how to do this please?

As a start, I've copied /boot/vmlinuz-3.2.0-4-amd64 and /boot/initrd.img-3.2.0-4-amd64 to /boot/vmlinuz.old and /boot/initrd.img.old, referenced them as a new entry in lilo.conf and run lilo, but I've a feeling it's not as simple as this.

i think some distros remove the previous kernel. just have a look what's in your /boot folder. on my debian based crunchbang there's a set of 4 files, all with the same version numbers. if you have more than 1 set, you most probably still have the older kernel and it's relatively easy to construct a boot command, only the version numbers change.

I only have the two files I mentioned above, which appear to get over-written each time there's a kernel update.

Perhaps there's a way to configure apt to not do this?