http://updates-http.cdn-apple.com/2019/cert/061-39476-20191023-48f365f4-0015-4c41-9f44-39d3d2aca067/InstallOS.dmg
Ensure your system time matches the era of the operating system using the Terminal date command mentioned above, or recreate the bootable USB drive using a freshly downloaded installer file. work download macos sierra 1012 6
Select your target hard drive (usually Macintosh HD) and click . http://updates-http
Click on the public directory routing to the Apple Mac App Store: macOS Sierra Page . work download macos sierra 1012 6