Better looking ISO image structure. Fixed issue with 'ghost' overlay bundles. Prepared the source structure for future UEFI enhancements.

src/.config

@@ -39,6 +39,22 @@ SYSLINUX_SOURCE_URL=http://kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.0
 #                                                  #
 ####################################################
 
+# This property is not used at the moment.
+#
+# This property defines the firmware compatibility. You can specify on what
+# systems MLL will be bootable.
+#
+#  bios - the generated ISO image will be compatible with legacy BIOS systems.
+#         This is the defaut option and it does not require root privileges
+#
+#  uefi - the generated ISO image will be compatible with UEFI systems. This
+#         option requires root privileges.
+#
+#  both - the generated ISO image will be compatible with both legacy BIOS and
+#         modern UEFI systems. This option requires root privileges.
+#
+FIRMWARE_TYPE=bios
+
 # Use predefined '.config' file when building the kernel. This overrides the
 # config generation in 'xx_build_kernel.sh' and the build process uses the
 # config file provided in this parameter. Place the configuration file here:
@@ -146,7 +162,7 @@ OVERLAY_TYPE=folder
 #
 # The default overlay bundles are 'dhcp' and 'mll_source'.
 #
-OVERLAY_BUNDLES=dhcp,mll_source,kernel_modules
+OVERLAY_BUNDLES=dhcp,mll_source
 
 # The location where the overlay bundle software will be stored.
 #
@@ -162,8 +178,8 @@ OVERLAY_LOCATION=iso
 
 # Use already downloaded source bundles instead of downloading them from
 # internet. This is useful when you have already downloaded the sources and have
-# no internet connection. Or if you want to share your version of "Minimal Linux
-# Live" with predefined sources.
+# no internet connection, or if you want to share your version of 'Minimal Linux
+# Live' with predefined sources.
 #
 USE_LOCAL_SOURCE=false
 

src/13_prepare_iso.sh

@@ -14,19 +14,23 @@ WORK_SYSLINUX_DIR=`ls -d $WORK_DIR/syslinux/syslinux-*`
 echo "Removing old ISO image work area. This may take a while."
 rm -rf $ISOIMAGE
 
-# This is the root folder of the ISO image.
 echo "Preparing new ISO image work area."
 mkdir -p $ISOIMAGE
 
+# This is the folder where we keep legacy BIOS boot artifacts.
+mkdir -p $ISOIMAGE/boot
+
 # Now we copy the kernel.
-cp $KERNEL_INSTALLED/kernel $ISOIMAGE/kernel.xz
+cp $KERNEL_INSTALLED/kernel \
+  $ISOIMAGE/boot/kernel.xz
 
 # Now we copy the root file system.
-cp $WORK_DIR/rootfs.cpio.xz $ISOIMAGE/rootfs.xz
+cp $WORK_DIR/rootfs.cpio.xz \
+  $ISOIMAGE/boot/rootfs.xz
 
 # Now we copy the overlay content if it exists
 if [ -d $ISOIMAGE_OVERLAY \
-  -a ! "`ls $ISOIMAGE`" = "" ] ; then
+  -a ! "`ls $ISOIMAGE_OVERLAY`" = "" ] ; then
 
   echo "The ISO image will have overlay structure."
   cp -r $ISOIMAGE_OVERLAY/* $ISOIMAGE
@@ -34,84 +38,26 @@ else
   echo "The ISO image will have no overlay structure."
 fi
 
-# Copy the precompiled files 'isolinux.bin' and 'ldlinux.c32' in the ISO image
-# root folder.
-cp $WORK_SYSLINUX_DIR/bios/core/isolinux.bin $ISOIMAGE
-cp $WORK_SYSLINUX_DIR/bios/com32/elflink/ldlinux/ldlinux.c32 $ISOIMAGE
-
-# Create the ISOLINUX configuration file.
-cat << CEOF > $ISOIMAGE/syslinux.cfg
-PROMPT 1
-TIMEOUT 50
-DEFAULT mll
-
-SAY
-SAY   ##################################################################
-SAY   #                                                                #
-SAY   #  Press <ENTER> to boot Minimal Linux Live or wait 5 seconds.   #
-SAY   #                                                                #
-SAY   #  Press <TAB> to view available boot entries or enter Syslinux  #
-SAY   #  commands directly.                                            #
-SAY   #                                                                #
-SAY   ##################################################################
-SAY 
-
-LABEL mll
-        LINUX kernel.xz
-        APPEND vga=ask
-        INITRD rootfs.xz
-
-LABEL mll_nomodeset
-        LINUX kernel.xz
-        APPEND vga=ask nomodeset
-        INITRD rootfs.xz
-CEOF
-
-# Create UEFI start script '/efi/boot/startup.nsh'. This script should be
-# executed by the firmware on boot if there is no UEFI compatible 'eltorito'
-# boot image in the ISO image *and* the UEFI boot shell is enabled.
+# Add the Syslinux configuration files for legacy BIOS and additional
+# UEFI startup script.
 #
-# Currently MLL doesn't provide native UEFI stub for boot manager and this
-# script is the only UEFI compliant way to pass the execution from the
-# firmware to the kernel. All this script does is to execute the kernel
-# which is masquaraded as PE/COFF image and pass arguments to the kernel,
-# e.g. 'initrd=<initramfs_archive>' and 'nomodeset'.
-#
-# Currently the 'startup.nsh' approach is most likely not universally
-# compatible. For example, this approach most probably will fail on UEFI
-# systems where the boot shell is missing or it is disabled.
-mkdir -p $ISOIMAGE/EFI/boot
-cat << CEOF > $ISOIMAGE/EFI/boot/startup.nsh
-echo -off
-echo Minimal Linux Live is starting.
-\\kernel.xz initrd=\\rootfs.xz nomodeset
+# The existing UEFI startup script does not guarantee that you can run
+# MLL on UEFI systems. This script is invoked only in case your system
+# drops you in UEFI shell with support level 1 or above. See UEFI shell
+# specification 2.2, section 3.1. Depending on your system configuration
+# you may not end up with UEFI shell even if your system supports it.
+# In this case MLL will not boot and you will end up with some kind of
+# UEFI error message.
+cp -r $SRC_DIR/minimal_boot/bios/* \
+  $ISOIMAGE
 
-CEOF
-
-# UEFI hacks BEGIN
-#
-# These files have no impact on the BIOS boot process. In
-# UEFI boot shell navigate to 'EFI/minimal' and try to
-# execute 'bootia32.efi' or 'bootx64.efi'.
-#
-# TODO - remove before next MLL release or fix the UEFI issue.
-#        The proper way to fix the UEFI issue is to provide
-#        secondary 'eltorito' boot image which is FAT32 and
-#        contains proper /EFI/boot/xxx files.
-
-mkdir -p $ISOIMAGE/EFI/minimal
-
-cp $WORK_SYSLINUX_DIR/efi32/efi/syslinux.efi \
-  $ISOIMAGE/EFI/minimal/bootia32.efi
-cp $WORK_SYSLINUX_DIR/efi32/com32/elflink/ldlinux/ldlinux.e32 \
-  $ISOIMAGE/EFI/minimal
-
-cp $WORK_SYSLINUX_DIR/efi64/efi/syslinux.efi \
-  $ISOIMAGE/EFI/minimal/bootx64.efi
-cp $WORK_SYSLINUX_DIR/efi64/com32/elflink/ldlinux/ldlinux.e64 \
-  $ISOIMAGE/EFI/minimal
-
-# UEFI hacks END
+# Copy the precompiled files 'isolinux.bin' and 'ldlinux.c32'. These files
+# are used by Syslinux during the legacy BIOS boot process.
+mkdir -p $ISOIMAGE/boot/syslinux
+cp $WORK_SYSLINUX_DIR/bios/core/isolinux.bin \
+  $ISOIMAGE/boot/syslinux
+cp $WORK_SYSLINUX_DIR/bios/com32/elflink/ldlinux/ldlinux.c32 \
+  $ISOIMAGE/boot/syslinux
 
 cd $SRC_DIR
 

src/14_generate_iso.sh

@@ -14,18 +14,16 @@ fi
 
 cd $ISOIMAGE
 
-# Now we generate the ISO image file.
-xorriso \
-  -as mkisofs \
-  -R \
-  -r \
-  -o $SRC_DIR/minimal_linux_live.iso \
-  -b isolinux.bin \
-  -c boot.cat \
-  -input-charset UTF-8 \
+# Now we generate 'hybrid' ISO image file which can also be used on
+# USB flash drive, e.g. 'dd if=minimal_linux_live.iso of=/dev/sdb'.
+xorriso -as mkisofs \
+  -isohybrid-mbr $WORK_DIR/syslinux/syslinux-*/bios/mbr/isohdpfx.bin \
+  -c boot/syslinux/boot.cat \
+  -b boot/syslinux/isolinux.bin \
     -no-emul-boot \
     -boot-load-size 4 \
     -boot-info-table \
+  -o $SRC_DIR/minimal_linux_live.iso \
   $ISOIMAGE
 
 cd $SRC_DIR

src/README

@@ -1,7 +1,6 @@
-
 The easiest way to build 'Minimal Linux Live' is to run the following script:
 
-  sh build_minimal_linux_live.sh
+  ./build_minimal_linux_live.sh
 
 Note that the build process requires proper toolchain already installed and
 configured. Check the project website for more information:

src/minimal_boot/bios/EFI/BOOT/startup.nsh

@@ -0,0 +1,3 @@
+echo -off
+echo Minimal Linux Live is starting.
+\boot\kernel.xz initrd=\boot\rootfs.xz

src/minimal_boot/bios/boot/syslinux/syslinux.cfg

@@ -0,0 +1,24 @@
+PROMPT 1
+TIMEOUT 50
+DEFAULT mll
+
+SAY
+SAY   ##################################################################
+SAY   #                                                                #
+SAY   #  Press <ENTER> to boot Minimal Linux Live or wait 5 seconds.   #
+SAY   #                                                                #
+SAY   #  Press <TAB> to view available boot entries or enter Syslinux  #
+SAY   #  commands directly.                                            #
+SAY   #                                                                #
+SAY   ##################################################################
+SAY 
+
+LABEL mll
+        LINUX /boot/kernel.xz
+        APPEND vga=ask
+        INITRD /boot/rootfs.xz
+
+LABEL mll_nomodeset
+        LINUX /boot/kernel.xz
+        APPEND vga=ask nomodeset
+        INITRD /boot/rootfs.xz

src/minimal_boot/uefi/loader/entries/mll-x86.conf

@@ -0,0 +1,4 @@
+title Minimal Linux Live
+version x86
+efi /minimal/x86/kernel.xz
+options initrd=/minimal/x86/rootfs.xz

src/minimal_boot/uefi/loader/entries/mll-x86_64.conf

@@ -0,0 +1,4 @@
+title Minimal Linux Live
+version x86_64
+efi /minimal/x86_64/kernel.xz
+options initrd=/minimal/x86_64/rootfs.xz

src/minimal_boot/uefi/loader/loader.conf

@@ -0,0 +1,3 @@
+default mll-x86_64
+timeout 5
+editor 1