iPhone is disabled and iTunes does not recognize it?

Sometimes life as a home-sys-admin bring you nostalgic challenges. It has been a while since I needed to assist someone with an Apple device (thanks to the Android dominance) but a close family member that still relies on an aging Apple Eco-System has found herself in trouble. She forgot her PIN and thru repeated attempts was able to disable her iPhone. 

Yes, the dreaded "iPhone is disabled" but not with the nice "try again in X minute" - the "connect to iTunes" endgame version. Which means that some lady was extremely persistent and tried a wrong passcode more than 10 times which disabled her iPhone. 

Now, one of the reasons I don't really like Apple's approach to security is that there is a cultural clash between Apple's good UI culture, which caters for weak users and older users, and Apple's security culture, which doesn't really see these user's difficulties, and takes a stance which is way too harsh, in my mind. Personally, I'm a person of usage before security kind of sys-admin, which does not mean that I see security as unimportant, particularly in this day and age of pervasive computing. But let us face it - if security measures make you turn your own digital equipment into bricks, then something in the UI worked against you, instead of helping you. 

With this light intro aside, lets get into my sad odyssey. It took a while to understand all the required details (due to a long period of time since the user logged into iTunes with ANY of her devices) but happily , the choice to set two phone numbers in her account (which yours truly recommended a few years ago) turned out extremely useful now. And with one device working, it seemed like everything was going to turn out ok, only that ... it didn't. 

For some reason, the regular recovery process did not work. I followed the "If you forgot the passcode on your iPhone, or your iPhone is disabled" guide - 

1. Press and hold the Side (or Top) button until the power off slider appears.
2. Drag the slider to turn off your iPhone.
3. Connect your iPhone to your computer while holding the Home button.
4. Keep holding the Home button until you see the recovery mode screen.

but the recovery mode screen did not show up. iTunes was not recognizing the iPhone. I tried it on 3 different computers (two Windows PCs and when despair seemed to appear, one MacBook); I tried different USB-lightning cables (and verified them with an iPad); I tried a different order of steps. With hard reset and without. 

Nothing worked. 

iTunes did not recognize the iPhone. 

It seemed like a message about the aging iPhone becoming a brick was inevitable but I decided to check the factory reset options, willing to accept the potential price of loss of data in exchange for a once again functional cellphone. After some searches I finally found a good guide explaining how to get your iPhone to Device Firmware Update (DFU) Mode. 

Before moving ahead, if you got here because you too can't get your iTunes to see your iPhone, be aware that DFU is the parallel to factory reset in Androids. This means that all non backed up information will be lost. If your last back was taken years ago - this is the moment to lament or consider more searches, because there is no way back from that path. 

So, how to do a factory reset for an old iPhone? 

1. Plug the iPhone with a USB cable to your computer
2. Open itunes and make sure you are logged into your account 
3. Press both power and volume (lower) for 8 secs together (you can count to 8 slowly)
4. Then leave the power button and keep pressing the volume button until iTunes prompts a message that it has identified an iPhone in recovery. 

I was very happy to see taht from that point, Apple's iTunes recognized the iPhone, and took my hand and lead me all the way to a working iPhone. 

Sadly, we had no iPhone backup. It is REALLY important to keep such a backup. Gladly, the owner of the phone had also an iPad which I backed up during the previous struggles, and gladly, iTues was able to restore from the iPad backup all the required data to the iPhone, so the owner got a functional iPhone with all the contact list and main apps during the restore process.