document kernel copy scripts

2 files changed, 20 insertions, 0 deletions

diff --git a/config/hooks/kernel-image.sh.binary b/config/hooks/kernel-image.sh.binary
index 2b4d094..65ed75a 100755
--- a/config/hooks/kernel-image.sh.binary
+++ b/config/hooks/kernel-image.sh.binary
@@ -2,5 +2,20 @@
 
 set -e
 
+# This script is necessary for squashfs (or any not-plainroot) builds, where
+# the usual /live images end up inside the filesystem.
+
+# In these cases the kernel ships in three places, which is inefficient: 
+#   enclosing binary /live (mangled)
+#   rootfs /live (mangled)
+#   rootfs /boot (original)
+
 echo "(re)Copying in kernel images..."
 cp -a chroot/live/uInitrd chroot/live/uImage chroot/live/dtb binary/live/
+
+# This reduces final image size significantly; original raw kernel files are
+# still duplicated in /boot.
+# Don't stop on errors, because this script may have already been run.
+echo "Removing redundant kernel images..."
+rm binary/live/vmlinuz-* || true
+rm binary/live/initrd.img-* || true
diff --git a/config/hooks/kernel-image.sh.chroot b/config/hooks/kernel-image.sh.chroot
index 05d287c..84de114 100755
--- a/config/hooks/kernel-image.sh.chroot
+++ b/config/hooks/kernel-image.sh.chroot
@@ -6,6 +6,9 @@ set -e
 # generates uImage and uInitrd style files (for use with u-boot, as opposed to
 # syslinux-style images), and moves those files to /live.
 
+# See also kernel-image.sh.binary, which recopies files at the final binary
+# assembly stage.
+
 KERNELVERSION=`ls /boot/vmlinuz-* | sed -e "s/\/boot\/vmlinuz-//"`
 
 echo "Mangling kernel..."
@@ -31,6 +34,8 @@ rm -rf /tmp/initrd-repack
     -d initrd.img uInitrd )
 rm /boot/initrd.img
 
+# Useful to to this here because sometimes /live doesn't get created
+# otherwise...
 echo "Creating /live and copying in boot images..."
 mkdir -p /live
 mv /boot/uInitrd /boot/uImage /boot/dtb /live