@gordoooo_z
AFAIR these Macs had the option to download the image of recovery partition from Apple's severs if it's not found on the hard drive. Question is, how does it connect to the Internet? If you ever configured wireless network in Mac OS X, it saves the ssid and key to EFI, so it's probably using that.
@gordoooo_z
Not sure when such an option was introduced, but it might not ๐
The EFI part itself can make a recovery partition, download the recovery image โ which is relatively small as it doesn't include complete OS installation files and restore it on the partition it has created.
So it might work even with no OS at all, basically with a blank hard drive.
It then proceeds to reboot from that recovery partition, downloads OS installation files and you can re-install the OS normally.
@gordoooo_z
At least that is how it was supposed to work, I'm not sure when this Internet recovery thing was introduced even, AFAIK, my 2011 MBP can't do it, but I had an iMac from the same era in the office and I tried it once โ it worked!