1. Install intel-microcode and its dependency from slackbuilds.org using the sbopkg package manager.
2. Generate the initrd for the generic kernel by running the pkgtool command and select setup and select the mkinitrd script to generate initrd.
3. Change into /boot directory
4. Rename the initrd.gz as initrd-1.gz with mv -v /boot/initrd.gz /boot/initrd-1.gz
5. now run the command
cat /boot/intel-ucode.cpio /boot/initrd-1.gz > /boot/initrd-intel.gz
6. Remove the old initrd by rm -rvf /boot/initrd-1.gz
7. Create a symlink ln -sv /boot/initrd-intel.gz /boot/initrd.gz
8. Update Lilo with lilo -v
9. The above steps are for the generic kernel in slackware. For the huge kernel
add the line intird=/boot/initrd-ucode.cpio in the /etc/lilo.conf
image = /boot/vmlinuz
initrd = /boot/intel-ucode.cpio
root = /dev/sdaX #[X being the linux partition ]
label = Linux
read-only
10. Run lilo -v
11. To check if the intel-microcode has been applied download the
spectre-meltdown-checkup script from
https://github.com/speed47/spectre-meltdown-checker
Run this script as root it should show STATUS: NOT VULNERABLE
This how to is from
https://forum.salixos.org/viewtopic.php?t=8171