demitri

# Since Contents/Resources/createinstallmedia command doesn't work, we need to manually create an disk image.

# Mount InstallESD.dmg
hdiutil mount /Applications/Install\ OS\ X\ 10.10\ Developer\ Preview.app/Contents/SharedSupport/InstallESD.dmg 

# Create a temporary writable BaseSystem image.
hdiutil convert /Volumes/OS\ X\ Install\ ESD/BaseSystem.dmg -format UDRW -o rw.dmg

# Get required sectors for packages.
# You'll get these numbers.