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@agentsim
Created June 10, 2017 02:23
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Create bootable ISO from HighSierra Installer
# Generate a BaseSystem.dmg with 10.13 Install Packages
hdiutil attach /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/SharedSupport/InstallESD.dmg -noverify -mountpoint /Volumes/highsierra
hdiutil create -o /tmp/HighSierraBase.cdr -size 7316m -layout SPUD -fs HFS+J
hdiutil attach /tmp/HighSierraBase.cdr.dmg -noverify -mountpoint /Volumes/install_build
asr restore -source /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/SharedSupport/BaseSystem.dmg -target /Volumes/install_build -noprompt -noverify -erase
cp -R /Volumes/highsierra/Packages /Volumes/OS\ X\ Base\ System/System/Installation
hdiutil detach /Volumes/OS\ X\ Base\ System/
hdiutil detach /Volumes/highsierra/
mv /tmp/HighSierraBase.cdr.dmg /tmp/BaseSystem.dmg
# Restore the 10.13 Installer's BaseSystem.dmg into file system and place custom BaseSystem.dmg into the root
hdiutil create -o /tmp/HighSierra.cdr -size 8965m -layout SPUD -fs HFS+J
hdiutil attach /tmp/HighSierra.cdr.dmg -noverify -mountpoint /Volumes/install_build
asr restore -source /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/SharedSupport/BaseSystem.dmg -target /Volumes/install_build -noprompt -noverify -erase
cp /tmp/BaseSystem.dmg /Volumes/OS\ X\ Base\ System
hdiutil detach /Volumes/OS\ X\ Base\ System/
hdiutil convert /tmp/HighSierra.cdr.dmg -format UDTO -o /tmp/HighSierra.iso
mv /tmp/HighSierra.iso.cdr ~/Desktop/HighSierra.iso
rm /tmp/HighSierra.cdr.dmg
@RudraSen2
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Generate ISO (New Method) Requires macOS Catalina+:

softwareupdate --fetch-full-installer --full-installer-version 10.13.6
sudo hdiutil create -o /tmp/HighSierra -size 16384m -volname HighSierra -layout SPUD -fs HFS+J
sudo hdiutil attach /tmp/HighSierra.dmg -noverify -mountpoint /Volumes/HighSierra
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/HighSierra --nointeraction
hdiutil eject -force /Volumes/Install\ macOS\ High\ Sierra
hdiutil convert /tmp/HighSierra.dmg -format UDTO -o ~/Desktop/HighSierra
mv -v ~/Desktop/HighSierra.cdr ~/Desktop/HighSierra.iso
sudo rm -fv /tmp/HighSierra.dmg

You should end up with a High Sierra ISO File in your Desktop

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