reinstall macOS using macOS Recovery methods
i have an old iMac 10.5.8 and trying to reinstall macOS that came with it but unable to start up using macOS recovery methods.
when powerup system, i press Shift-Option-⌘-R, but it's not working.
system starts up normally at login prompt without the Recovery menu.
i tried Command (⌘)-R, and Option-⌘-R as well but not working.
these steps are from https://support.apple.com/en-us/HT204904
so what else can i do?