Wiped all disks for Ubuntu installation, but “macOS Recovery over the Internet” still knows my Wi-Fi password

Question

I wiped all disks for Ubuntu installation. The macOS Recovery partition was gone.

Decided after half of an year, to install again macOS with macOS Recovery over the Internet

If you can't start up from macOS Recovery

If your Mac can't start up from its built-in macOS Recovery system, it might try to start up from macOS Recovery over the Internet. When that happens, you see a spinning globe instead of an Apple logo during

I was very much surprised the this "macOS Recovery over the Internet" knows my Wi-Fi password.

He didn't ask for password and begin download stuff off the internet.

Can you explain why he remembers my Wi-Fi password?

Answer 1

Your Mac contains forms of storage that are persistent, but not stored on your normal disk drive - it is known as NVRAM (Non-volatile RAM) and PRAM (parameter RAM).

This persistent storage is used by the computer to remember user preferences such as which disk drive to boot from by default, audio volume settings, etc. It also contains the password for your WiFi.

The Internet Recovery mode is able to access this storage to obtain an internet connection to Apple's server for downloading the necessary software.

If you wish to clear this storage, you can do so by holding down Cmd-Opt-P-R and then turning on the Mac - hold them down for half a minute or so.

NOTE: If you have set a firmware password, you'll need to disable this before you can clear the persistent storage.