diff --git a/README.md b/README.md
index 8257fc8..fd0b552 100644
--- a/README.md
+++ b/README.md
@@ -93,6 +93,9 @@ Set default system timezone. All available timezones can be found in the `/usr/s
 ##### `EXPANDROOT`=true
 Expand the root partition and filesystem automatically on first boot.
 
+##### `ENABLE_SWAP`=true
+Enable swap. The size of the swapfile is chosen relative to the size of the root partition. It'll use the `dphys-swapfile` package for that.
+
 ##### `ENABLE_QEMU`=false
 Generate kernel (`vexpress_defconfig`), file system image (`qcow2`) and DTB files that can be used for QEMU full system emulation (`vexpress-A15`). The output files are stored in the `$(pwd)/images/qemu` directory. You can find more information about running the generated image in the QEMU section of this readme file.
 
diff --git a/bootstrap.d/50-firstboot.sh b/bootstrap.d/50-firstboot.sh
index cc76f34..b8c31a3 100644
--- a/bootstrap.d/50-firstboot.sh
+++ b/bootstrap.d/50-firstboot.sh
@@ -10,28 +10,33 @@ cat files/firstboot/10-begin.sh > "${ETC_DIR}/rc.firstboot"
 
 # Ensure openssh server host keys are regenerated on first boot
 if [ "$ENABLE_SSHD" = true ] ; then
-  cat files/firstboot/21-generate-ssh-keys.sh >> "${ETC_DIR}/rc.firstboot"
+  cat files/firstboot/20-generate-ssh-keys.sh >> "${ETC_DIR}/rc.firstboot"
 fi
 
 # Prepare filesystem auto expand
 if [ "$EXPANDROOT" = true ] ; then
   if [ "$ENABLE_CRYPTFS" = false ] ; then
-    cat files/firstboot/22-expandroot.sh >> "${ETC_DIR}/rc.firstboot"
+    cat files/firstboot/30-expandroot.sh >> "${ETC_DIR}/rc.firstboot"
+
+    # Restart dphys-swapfile so the size of the swap file is relative to the resized root partition
+    if [ "$ENABLE_SWAP" = true ] ; then
+      cat files/firstboot/31-restart-dphys-swapfile.sh >> "${ETC_DIR}/rc.firstboot"
+    fi
   else
     # Regenerate initramfs to remove encrypted root partition auto expand
-    cat files/firstboot/23-regenerate-initramfs.sh >> "${ETC_DIR}/rc.firstboot"
+    cat files/firstboot/33-regenerate-initramfs.sh >> "${ETC_DIR}/rc.firstboot"
   fi
 fi
 
 # Ensure that dbus machine-id exists
-cat files/firstboot/24-generate-machineid.sh >> "${ETC_DIR}/rc.firstboot"
+cat files/firstboot/40-generate-machineid.sh >> "${ETC_DIR}/rc.firstboot"
 
 # Create /etc/resolv.conf symlink
-cat files/firstboot/25-create-resolv-symlink.sh >> "${ETC_DIR}/rc.firstboot"
+cat files/firstboot/41-create-resolv-symlink.sh >> "${ETC_DIR}/rc.firstboot"
 
 # Configure automatic network interface names
 if [ "$ENABLE_IFNAMES" = true ] ; then
-  cat files/firstboot/26-config-ifnames.sh >> "${ETC_DIR}/rc.firstboot"
+  cat files/firstboot/42-config-ifnames.sh >> "${ETC_DIR}/rc.firstboot"
 fi
 
 # Finalize rc.firstboot script
diff --git a/files/firstboot/21-generate-ssh-keys.sh b/files/firstboot/20-generate-ssh-keys.sh
similarity index 100%
rename from files/firstboot/21-generate-ssh-keys.sh
rename to files/firstboot/20-generate-ssh-keys.sh
diff --git a/files/firstboot/22-expandroot.sh b/files/firstboot/30-expandroot.sh
similarity index 100%
rename from files/firstboot/22-expandroot.sh
rename to files/firstboot/30-expandroot.sh
diff --git a/files/firstboot/31-restart-dphys-swapfile.sh b/files/firstboot/31-restart-dphys-swapfile.sh
new file mode 100644
index 0000000..ad0c3a0
--- /dev/null
+++ b/files/firstboot/31-restart-dphys-swapfile.sh
@@ -0,0 +1,5 @@
+logger -t "rc.firstboot" "Restarting dphys-swapfile"
+
+if systemctl is-enabled dphys-swapfile ; then
+  systemctl restart dphys-swapfile
+fi
diff --git a/files/firstboot/23-regenerate-initramfs.sh b/files/firstboot/33-regenerate-initramfs.sh
similarity index 100%
rename from files/firstboot/23-regenerate-initramfs.sh
rename to files/firstboot/33-regenerate-initramfs.sh
diff --git a/files/firstboot/24-generate-machineid.sh b/files/firstboot/40-generate-machineid.sh
similarity index 100%
rename from files/firstboot/24-generate-machineid.sh
rename to files/firstboot/40-generate-machineid.sh
diff --git a/files/firstboot/25-create-resolv-symlink.sh b/files/firstboot/41-create-resolv-symlink.sh
similarity index 100%
rename from files/firstboot/25-create-resolv-symlink.sh
rename to files/firstboot/41-create-resolv-symlink.sh
diff --git a/files/firstboot/26-config-ifnames.sh b/files/firstboot/42-config-ifnames.sh
similarity index 100%
rename from files/firstboot/26-config-ifnames.sh
rename to files/firstboot/42-config-ifnames.sh
diff --git a/rpi23-gen-image.sh b/rpi23-gen-image.sh
index 575252a..2f90f95 100755
--- a/rpi23-gen-image.sh
+++ b/rpi23-gen-image.sh
@@ -83,6 +83,7 @@ USER_PASSWORD=${USER_PASSWORD:=raspberry}
 DEFLOCAL=${DEFLOCAL:="en_US.UTF-8"}
 TIMEZONE=${TIMEZONE:="Europe/Berlin"}
 EXPANDROOT=${EXPANDROOT:=true}
+ENABLE_SWAP=${ENABLE_SWAP:=true}
 
 # Keyboard settings
 XKB_MODEL=${XKB_MODEL:=""}
@@ -484,6 +485,11 @@ if [ "$EXPANDROOT" = true ] ; then
   APT_INCLUDES="${APT_INCLUDES},parted"
 fi
 
+# Add dphys-swapfile package, required to enable swap
+if [ "$ENABLE_SWAP" = true ] ; then
+  APT_INCLUDES="${APT_INCLUDES},dphys-swapfile"
+fi
+
 # Add dbus package, recommended if using systemd
 if [ "$ENABLE_DBUS" = true ] ; then
   APT_INCLUDES="${APT_INCLUDES},dbus"