LILO (Linux Loader) is a boot loader for Linux and the default bootloader for non EFI slackware installs.

we need multiple kernels to boot. whether you run stable or -current you want to always have a known working kernel to fall back on. first we will install the kernels of your choice using slackupdr

slackupdr

once your kernels are installed edit lilo.conf

nano /etc/lilo/conf

find the kernel stanza and we will expand it to include the new kernels. we are also going to add boot entries for huge versus generic kernels. find this stanza

# Linux bootable partition config begins
image = /boot/vmlinuz
  root = /dev/sda2
  label = huge
  read-only

we will add stanzas for the kernels we've installed

here is a default lilo.conf as generated by liloconfig

# LILO configuration file
# generated by 'liloconfig'
#
# Start LILO global section
# Append any additional kernel parameters:
append=" "

boot = /dev/sda
# This option loads the kernel and initrd much faster:
compact

# Boot BMP Image.
# Bitmap in BMP format: 640x480x8
  bitmap = /boot/slack.bmp
# Menu colors (foreground, background, shadow, highlighted
# foreground, highlighted background, highlighted shadow):
  bmp-colors = 255,0,255,0,255,0
# Location of the option table: location x, location y, number of
# columns, lines per column (max 15), "spill" (this is how many
# entries must be in the first column before the next begins to
# be used. We don't specify it here, as there's just one column.
  bmp-table = 60,6,1,16
# Timer location x, timer location y, foreground color,
# background color, shadow color.
  bmp-timer = 65,27,0,255

# Standard menu.
# Or, you can comment out the bitmap menu above and 
# use a boot message with the standard menu:
#message = /boot/boot_message.txt

# Wait until the timeout to boot (if commented out, boot the
# first entry immediately):
prompt
# Timeout before the first entry boots.
# This is given in tenths of a second, so 600 for every minute:
timeout = 1200
# Override dangerous defaults that rewrite the partition table:
change-rules
  reset
# Normal VGA console
vga = normal
# Ask for video mode at boot (time out to normal in 30s)
#vga = ask
# VESA framebuffer console @ 1024x768x64k
#vga=791
# VESA framebuffer console @ 1024x768x32k
#vga=790
# VESA framebuffer console @ 1024x768x256
#vga=773
# VESA framebuffer console @ 800x600x64k
#vga=788
# VESA framebuffer console @ 800x600x32k
#vga=787
# VESA framebuffer console @ 800x600x256
#vga=771
# VESA framebuffer console @ 640x480x64k
#vga=785
# VESA framebuffer console @ 640x480x32k
#vga=784
# VESA framebuffer console @ 640x480x256
#vga=769
# End LILO global section
# Linux bootable partition config begins
image = /boot/vmlinuz
  root = /dev/sda2
  label = Linux
  read-only
# Linux bootable partition config ends

prompt
timeout=50
boot=/dev/sda
root=/dev/sda2
lba32
compact
bitmap = /boot/Slackware_Moonboot.bmp
bmp-colors = 255,0,255,0,255,0
bmp-table = 60,6,1,16
bmp-timer = 65,27,0,255
append="mitigations=off"
vga=normal
default=Gen6.9.1
image=/boot/vmlinuz-generic-6.6.30
  label=Gen6.6.30
  initrd=/boot/initrd-6.6.30.gz
  read-only
image=/boot/vmlinuz-generic-6.9.1
  label=Gen6.9.1
  initrd=/boot/initrd-6.9.1.gz
  read-only
image=/boot/vmlinuz-huge-6.6.30
  label=Hug6.6.30
  read-only
image=/boot/vmlinuz-huge-6.9.1
  label=Hug6.9.1
  read-only