This downloads the standard .app file, not an ISO.
Download Install macOS High Sierra.app using the Apple link above. It will be saved in your /Applications folder. Macos High Sierra 10.13 Download -2021- Iso
(Replace MyUSB with your USB drive name). 4. Boot your Mac holding Option -> Select the USB. This downloads the standard
: Disconnect from the internet and change your system date to a time closer to 2018 (e.g., date 0101010118 in Terminal). This downloads the standard .app file