Configure LILO on Slackware with a fallback kernel

Before running lilo, keep at least one working boot entry. A mistake in lilo.conf can make the system unbootable with the new kernel.

1. Initial checks

ls -lh /boot
uname -r
ls /lib/modules

Identify:

New generic kernel (e.g. /boot/vmlinuz-generic-6.x.y)
Matching initrd (e.g. /boot/initrd-6.x.y.gz)
Fallback kernel (previous or huge)

2. Backup lilo.conf

cp /etc/lilo.conf /etc/lilo.conf.backup-$(date +%F)

3. Example configuration with two entries

One main entry (generic + initrd) and one fallback.

boot = /dev/sda
prompt
timeout = 100
default = Linux-generic

image = /boot/vmlinuz-generic-6.x.y
  initrd = /boot/initrd-6.x.y.gz
  root = /dev/sda2
  label = Linux-generic
  read-only

image = /boot/vmlinuz-huge-6.x.y
  root = /dev/sda2
  label = Linux-huge
  read-only

# previous fallback
image = /boot/vmlinuz-generic-prev
  initrd = /boot/initrd-prev.gz
  root = /dev/sda2
  label = Linux-prev
  read-only

Adjust boot= (MBR/partition), root=, kernel/initrd paths, and labels to your real values.

4. Run LILO correctly

lilo -v

Check output: the added labels should appear without errors.

If lilo -v completes successfully, the changes were written to the bootloader.

5. Common errors

Kernel/initrd file not found: wrong path in lilo.conf
Wrong root device: kernel boots but cannot mount root
Missing initrd with generic kernel
Forgot lilo -v: file updated but bootloader not

6. Rollback strategy

At boot select Linux-prev or Linux-huge
Fix /etc/lilo.conf
Rebuild initrd if needed
Run lilo -v again

7. Best practices

Always keep a fallback entry
Use short, clear labels
Comment old entries before removing them permanently
After kernel updates: new initrd + update lilo immediately

Quick checklist

[ ] /etc/lilo.conf backed up
[ ] Generic + initrd entry added
[ ] Fallback entry present
[ ] /boot paths verified
[ ] lilo -v executed without errors
[ ] New entry boot tested

Back to the Linux HowTo section