I would like to upgrade the Debian stock kernel to a compiled kernel packed as a .deb package.
Running the:
dpkg -i linux-image-x.x.Custom_amd64.deb
triggers the grub-update and, as I see from filesystem, the creation of the initrd file.
But now, how I tell EXTLINUX to boot from the new kernel?
There is nothing different introduced by Debian: install extlinux as usual with:
make sure kernel image is present with matching initrd;
create a /boot/extlinux/extlinux.conf file like:
note the path are right in a box in which /boot is not a partition on its own (it is part of / partition).
If the kernel image is too large, use the keyword linux (not kernel).