iMac SSD upgrade – Firmware password lock My dad bought a used 21.5 iMac (2017) a few weeks back (previous owner bought it new but decided to sell after a week, so its basically new.) Given that it came with a 1TB fusion drive, we decided to switch it for the Samsung EVO he was using in his previous Macbook (He doesn’t need storage, only speed.)

All went according to plan in terms of opening and swapping the drives, but upon rebooting (attempting to ctrl+r to boot menu) it popped the apple logo and then swapped to a black screen with a lock and password field.
After a little reading on the subject it seems someone must have enabled the EFI Firmware password protection which doesn’t allow booting on other drives e.g. external or otherwise.

I’ve contacted the previous owner, but she's drawing a blank, claiming never setting up anything of the sort. I’m unsure if this can be enabled during first boot installation, but she didn’t strike me as the type who would know how to do so afterwards (let alone think about it.) My guess is that the shop might’ve had it returned from a prior owner, not reset it correctly and resold it as new (or perhaps discounted, hard to tell from the receipt.)

TL;DR

Knowing firmware is locked with an unobtainable password ... 


Would I be able to remove the new SSD and insert the original HDD and have
the password prompt go away? Or is the system locked until correct
password is entered, no matter the drive (it booted prior to
switching drives).
Warranty void on opening and swapping diskdrive? Searching around it
seems everyone has a different story. Some say the rest of the
system is still under warranty, others do not. This isn’t Apples
issue of cause, but I would likely levy it against the reseller.
Even if the old HDD would work again, I’m assuming that not having
the FW password would be a roadblock if reinstalling OSX in the
future?
This Apple document tells you everything you need to know about Firmware passwords.

The essential points for you are:


Your Mac asks for the firmware password only when attempting to start up from a storage device other than the one selected in Startup Disk preferences, or when starting up from macOS Recovery.
If you can't remember your firmware password or passcode, schedule an in-person service appointment with an Apple Store or Apple Authorized Service Provider. Bring your Mac to the appointment, and bring your original receipt or invoice as proof of purchase.


The Firmware password is not required for OS installation.

You will need to ask the original purchaser for their receipt or other proof of purchase.