hdiutil detach /Volumes/Install\ macOS\ High\ Sierra hdiutil convert /tmp/HighSierra.dmg -format UDTO -o ~/Desktop/HighSierra.iso
hdiutil create -o /tmp/HighSierra -size 8500m -volname HighSierra -layout SPUD -fs HFS+J
git clone https://github.com/corpnewt/gibMacOS cd gibMacOS python3 gibMacOS.py Choose the catalog (e.g., PublicRelease ) and select High Sierra 10.13.6.