update prelinkedkernel in mac os recovery hd, for hackintosh

update-recoveryhd.sh

#!/bin/sh
set -e
if [[ $EUID -ne 0 ]]; then
   exec sudo "$0"
   exit 1
fi
#ROOTDISK=$(mount|grep ' on / '|egrep -o 'disk\d*')
REC_DEV=$(diskutil info `df /|awk '/disk/ {print $1}'`|awk '/Recovery Disk:/ {print $3}')
#mkdir -p /Volumes/Recovery\ HD/
#mount -t hfs ${REC_DEV} /Volumes/Recovery\ HD/
diskutil mount ${REC_DEV}
cd /Volumes/Recovery\ HD/com.apple.recovery.boot/

#SYS_BUD=$(sw_vers -buildVersion)
#RH_BUD=$( awk '/<key>ProductBuildVersion<\/key>.*/,/<\/string>/' SystemVersion.plist | egrep -o '(<string>.*</string>)' | sed -e 's/<\/*string>//g')
#if [[ $SYS_BUD != $RH_BUD ]];then
#  echo "System Build Version does NOT match Recovery Build Version!!!"
#  echo "Aborting script."
#  exit 1
#fi

CURRENT_DARWIN_VER=$(uname -a|awk '{print $7}'|sed 's/://g')
ORIG_DARWIN_VER=$(strings prelinkedkernel|egrep -o "Kernel Version \S+"|egrep -o "\d[0-9.]+\d")
if [[ $CURRENT_DARWIN_VER != $ORIG_DARWIN_VER ]]
then
  echo "System Darwin Version does NOT match Recovery Darwin Version!!!"
  echo "Aborting script."
  exit 1
fi


rm -rf prelinkedkernel
cp /System/Library/PrelinkedKernels/prelinkedkernel /Volumes/Recovery\ HD/com.apple.recovery.boot/
touch prelinkedkernel
diskutil unmount force ${REC_DEV} >/dev/null