systemd-boot loader entries creation script (used on elementary OS 5.0)

gistfile1.txt

#!/bin/bash
#
# This is a simple custom kernel hook to populate the systemd-boot entries
# whenever kernels are added or removed during an update.
#
distroid=$(cat /etc/lsb-release | grep DISTRIB_ID | cut -d "=" -f 2)
distroname=$(cat /etc/lsb-release | grep DISTRIB_DESCRIPTION | cut -d "\"" -f 2)

# The name of your root partition
partition=$(cat /etc/fstab | grep "/ was on" | cut -d " " -f 5)

vmlinuz=$(find /boot -maxdepth 1 -name "vmlinuz-*-generic")
version=$(echo $vmlinuz | grep -o -P "\d+\.\d+\.\d+\-\d+" | sort -V | head -n -1)
latest=$(echo $vmlinuz | grep -o -P "\d+\.\d+\.\d+\-\d+" | sort -V | tail -n 1)
mkdir -p /boot/loader/entries/${distroid}/

echo ">> COPYING ${latest}-generic. LATEST VERSION."

cat << EOF > /boot/loader/entries/${distroid}.conf
title   ${distroname} - Current Kernel
linux   /${distroid}/vmlinuz-generic
initrd  /${distroid}/initrd.img-generic
options root=${partition} rw rootflags=subvol=@
EOF

for file in initrd.img vmlinuz; do
    cp "/boot/${file}-${latest}-generic" "/boot/loader/entries/${distroid}/${file}-generic"
done

for ver in $version; do

    echo ">> COPYING ${ver}-generic."

cat << EOF > /boot/loader/entries/${distroid}-${ver}.conf
title   ${distroname} - Kernel ${ver}
linux   /${distroid}/vmlinuz-${ver}-generic
initrd  /${distroid}/initrd.img-${ver}-generic
options root=${partition} rw rootflags=subvol=@
EOF

    for file in initrd.img vmlinuz; do
        cp "/boot/${file}-${ver}-generic" "/boot/loader/entries/${distroid}/${file}-${ver}-generic"
    done
done

Use at your own risk, etc.