Recently (Fall 2020) I was able to purchase an old MacBook Air for my daughter to use. It is an older device, but working just fine for what she wanted. The original owner had not removed his account, and I had no admin password, so I decided to just do a reinstall. Very bad move on my part.

Apple really builds good hardware, but they don't want you to keep it too long. So, after a point, they kill the SSL keys on the repository, meaning you can no longer reinstall using the built in functions.

Rebooted the system, pressed Apple-R to go into recovery mode, and told the system to reinstall itself. After formatting the drive and starting the install, I get a timer stating it is going to take -2,393,938,938 and 8 minutes. A couple of minutes later, a message appears stating it can not download additional components needed to install OS X. Basically, the same issue described at https://www.ifixit.com/Answers/View/601830/re+installing+OSX+problems.

Finally got it installed. I had a friend who had a full system backup who was able to take that image and copy it to the MacBook, and it worked just fine. Then, my daughter tried to install some software which corrupted the machine, so she brought it back to me to repair.

Not being an total idiot, I made a full TimeMachine backup before I gave the machine to my daughter, so I thought “no problem, I'll just recover from TimeMachine”. Didn't work.

• Burn DMG to USB https://www.androidphonesoft.com/resources/burn-dmg-to-usb-drive.html
• Restore a full-disk .dmg file to raw block device http://hints.macworld.com/article.php?story=2009041216314856
• check status of dd https://www.commandlinefu.com/commands/view/11666/check-the-status-of-dd-in-progress-os-x
• Resize Mac HD Partition https://medium.com/@kepler.donald/how-to-resize-a-mac-hd-partition-to-utilize-the-available-free-space-c4aac79b6347
• Discussion of OSX Installation Issues https://www.ifixit.com/Answers/View/601830/re+installing+OSX+problems
• Mount DMG from CLI https://osxdaily.com/2011/12/17/mount-a-dmg-from-the-command-line-in-mac-os-x/
• Restore OS from Time Machine backup https://support.apple.com/en-us/HT202406
• Mac Startup Key Combinations https://support.apple.com/en-us/HT201255