Implemented another level of "early shell". Now we have 2 early shells - one right after the initial mount procedure and another one right after the overlay procedure.

src/08_generate_rootfs/etc/02_overlay.sh

@@ -159,7 +159,7 @@ for DEVICE in /dev/* ; do
 done
 
 # Move critical file systems to the new mountpoint.
-echo "Remounting /dev, /sys, /tmp and /proc in /mnt..."
+echo "Remounting /dev, /sys, /tmp and /proc in /mnt."
 mount --move /dev /mnt/dev
 mount --move /sys /mnt/sys
 mount --move /proc /mnt/proc
@@ -168,6 +168,7 @@ mount --move /tmp /mnt/tmp
 # 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.
+echo "Moving from initramfs root area to overlayfs root area."
 exec switch_root /mnt /etc/03_init.sh
 
 echo "(/etc/02_overlay.sh) - there is a serious bug..."

src/08_generate_rootfs/etc/03_init.sh

@@ -37,13 +37,15 @@
 #
 # exec /sbin/init
 
+# Print message on screen.
 cat << CEOF
 
-  Wait 5 seconds for the default system initialization process based on the
+  Wait 5 seconds for the system initialization process or press any key for
-  files /sbin/init and /etc/inittab or press any key for PID 1 shell.
+  PID 1 shell outside of the initramfs area.
 
 CEOF
 
+# Wait 5 second or until any keybord key is pressed.
 read -t 5 -n1 -s key
 
 if [ "$key" = "" ] ; then
@@ -51,20 +53,23 @@ if [ "$key" = "" ] ; then
   echo "Executing /sbin/init as PID 1."
   exec /sbin/init
 else
-
+  # Print message on screen.
-# Using no indentation for this snippet or otherwise it causes kernel panic.
   cat << CEOF
-
+  This is PID 1 shell outside of the initramfs area. Execute the following in
-  This is PID 1 shell. Execute the following in order to continue with the
+  order to continue with the system initialization.
-  default system initialization process:
 
   exec /sbin/init
 
 CEOF
 
+  if [ "$PID1_SHELL" = "true" ] ; then
+    # PID1_SHELL flag is set which means we have controlling terminal.
+    exec sh
+  else
     # Interactive shell with controlling tty as PID 1.
     exec setsid cttyhack sh
   fi
+fi
 
 echo "(/etc/03_init.sh) - there is a serious bug..."
 

src/08_generate_rootfs/init

@@ -31,6 +31,39 @@ echo "Welcome to \"Minimal Linux Live\" (/init)"
 # Let's mount all core file systems.
 /etc/01_prepare.sh
 
+# Print message on screen.
+cat << CEOF
+
+  Wait 5 seconds to continue with overlay initialization process or press any
+  key for PID 1 shell inside the initramfs area.
+
+CEOF
+
+# Wait 5 second or until any keybord key is pressed.
+read -t 5 -n1 -s key
+
+if [ ! "$key" = "" ] ; then
+  # Print message on screen.
+  cat << CEOF
+  This is PID 1 shell inside the initramfs area. Execute the following in order
+  to continue with the overlay initialization process.
+
+  exec /etc/02_overlay.sh
+  
+  Execute the following in order to skip the overlay initialization and continue
+  directly with the system initialization:
+
+  exec /sbin/init
+
+CEOF
+
+  # Set flag which indicates that we have obtained controlling terminal.
+  export PID1_SHELL=true
+  
+  # Interactive shell with controlling tty as PID 1.
+  exec setsid cttyhack sh
+fi
+
 # Create new mountpoint in RAM, make it our new root location and overlay it
 # with our storage area (if overlay area exists at all). This operation invokes
 # the script '/etc/03_init.sh' as the new init process.