diff --git a/src/02_build_kernel.sh b/src/02_build_kernel.sh
index 65ebe9f75..c48a546b3 100755
--- a/src/02_build_kernel.sh
+++ b/src/02_build_kernel.sh
@@ -14,6 +14,9 @@ make defconfig
# Changes the name of the system to 'minimal'.
sed -i "s/.*CONFIG_DEFAULT_HOSTNAME.*/CONFIG_DEFAULT_HOSTNAME=\"minimal\"/" .config
+# Enable overlay support, e.g. merge ro and rw directories.
+sed -i "s/.*CONFIG_OVERLAY_FS.*/CONFIG_OVERLAY_FS=y/" .config
+
# Compile the kernel with optimization for "parallel jobs" = "number of processors".
# Good explanation of the different kernels:
# http://unix.stackexchange.com/questions/5518/what-is-the-difference-between-the-following-kernel-makefile-terms-vmlinux-vmlinux
diff --git a/src/08_generate_rootfs.sh b/src/08_generate_rootfs.sh
index 1446f6bdc..54ca25ad6 100755
--- a/src/08_generate_rootfs.sh
+++ b/src/08_generate_rootfs.sh
@@ -54,8 +54,8 @@ EOF
chmod +x prepare.sh
# The script '/etc/switch.sh' is automatically executed as part of the '/init'
-# process. We copy all files/folders to new mountpoint and then execute the
-# command 'switch_root'.
+# process. We overlay the '/minimal/rootfs' folder from the boot media, copy all
+# files and folders to new mountpoint and then execute the command 'switch_root'.
cat > switch.sh << EOF
#!/bin/sh
@@ -63,28 +63,74 @@ cat > switch.sh << EOF
mount -t tmpfs none /mnt
# Create folders for all crytical file systems.
+echo "Create folders for all crytical file systems..."
mkdir /mnt/dev
mkdir /mnt/sys
mkdir /mnt/proc
mkdir /mnt/tmp
+echo "...done."
-# Move all crytical file systems in the new mountpoint.
+# Copy root folders in the new mountpoint.
+echo "Copying the root file system to /mnt..."
+cp -a bin etc lib lib64 root sbin src usr /mnt
+echo "...done."
+
+mkdir /tmp/mnt
+echo "Searching available devices for /minimal/rootfs folder..."
+for DEVICE in /dev/* ; do
+ DEV=\$(echo "\${DEVICE##*/}")
+ SYSDEV=\$(echo "/sys/class/block/\$DEV")
+
+ case \$DEV in
+ *loop*) continue ;;
+ esac
+
+ if [ ! -d "\$SYSDEV" ] ; then
+ continue
+ fi
+
+ mount \$DEVICE /tmp/mnt 2>/dev/null
+ if [ -d /tmp/mnt/minimal/rootfs ] ; then
+ echo " Found /minimal/rootfs folder on device \$DEV."
+
+ touch /tmp/mnt/minimal/rootfs/minimal.pid 2>/dev/null
+ if [ -f /tmp/mnt/minimal/rootfs/minimal.pid ] ; then
+ echo " Trying to overlay in read/write mode..."
+ rm -f /tmp/mnt/minimal/rootfs/minimal.pid
+ mount -t overlay -o lowerdir=/mnt,upperdir=/tmp/mnt/minimal/rootfs,workdir=/tmp/mnt/minimal/work none /mnt
+ OUT=\$?
+ if [ ! "\$OUT" = "0" ] ; then
+ echo " Mount failed (probably on vfat), moving on with other devices."
+ continue
+ fi
+ else
+ echo " Trying to overlay in read only mode..."
+ mkdir -p /tmp/minimal/work
+ mkdir -p /tmp/minimal/rootfs
+ mount -t overlay -o lowerdir=/mnt:/tmp/mnt/minimal/rootfs,upperdir=/tmp/minimal/rootfs,workdir=/tmp/minimal/work none /mnt
+ fi
+
+ echo " ...done."
+
+ break
+ else
+ umount /tmp/mnt 2>/dev/null
+ fi
+done
+echo "...done."
+
+# Move crytical file systems to the new mountpoint.
echo "Remounting /dev, /sys, /tmp and /proc in /mnt..."
mount --move /dev /mnt/dev
mount --move /sys /mnt/sys
-mount --move /tmp /mnt/tmp
mount --move /proc /mnt/proc
-echo "...done."
-
-# Copy all root folders in the new mountpoint.
-echo "Moving the rest of the root file system to /mnt..."
-cp -a bin etc lib lib64 root sbin src usr /mnt
+mount --move /tmp /mnt/tmp
echo "...done."
# The new mountpoint becomes file system root. All original root folders are
# deleted automatically as part of the command execution. The '/sbin/init'
-# process is invoked and it becomes the new PID 1 parent process.
-exec switch_root /mnt/ /sbin/init
+# process is invoked and it becomes the new PID 1 parent process.
+exec switch_root /mnt /sbin/init
echo "You can never see this... unless there is a serious bug..."
sleep 99999
diff --git a/src/11_generate_iso.sh b/src/11_generate_iso.sh
index bebe36154..b6ede9699 100755
--- a/src/11_generate_iso.sh
+++ b/src/11_generate_iso.sh
@@ -41,6 +41,14 @@ chmod +rx src/*.sh
chmod +r src/.config
chmod +r src/*.txt
+# Create the overlay directory '/minimal'. All files in this folder are merged
+# in the root folder and can be manipulated thanks to overlayfs.
+mkdir -p minimal/rootfs
+cd minimal/rootfs
+echo 'Sample file 1 from CD.' > file_from_cd_1.txt
+echo 'Sample file 2 from CD.' > file_from_cd_2.txt
+cd ../..
+
# Create ISOLINUX configuration file.
echo 'default kernel.bz initrd=rootfs.gz' > ./isolinux.cfg
diff --git a/src/qemu32.sh b/src/qemu32.sh
index 3d0ca2a92..aae299241 100755
--- a/src/qemu32.sh
+++ b/src/qemu32.sh
@@ -1,4 +1,4 @@
#!/bin/sh
-qemu-system-i386 -m 64M -cdrom minimal_linux_live.iso
+qemu-system-i386 -m 64M -hda hdd.img -cdrom minimal_linux_live.iso -boot d
diff --git a/src/qemu64.sh b/src/qemu64.sh
index 34392b5ce..2af546eff 100755
--- a/src/qemu64.sh
+++ b/src/qemu64.sh
@@ -1,4 +1,4 @@
#!/bin/sh
-qemu-system-x86_64 -m 64M -cdrom minimal_linux_live.iso
+qemu-system-x86_64 -m 64M -hda hdd.img -cdrom minimal_linux_live.iso -boot d