I came back here after managing a fix for it and hoping this would help those who have been through the frustration with this issue like me. Here's what you need to do:
Having a MacBook and a cable to connect your iPhone to it, plug your iphone into Macbook.
Please be patient when trying to put your iPhone in DFU mode (it could take more than 10 times like I did, see the image attached about DFU mode screen).
2. a) Press the Volume Up button (quickly no need to hold), then release it.
2. b) Press the Volume Down (quickly no need to hold), then release it.
2. c) Press and hold the Power button until you see the Apple logo on a black screen (if at this step your phone only restarts and then you see the f Hello screen again, please go back to step 2a and re-tried, and you need to be patient).
2.d) Right when you see the Apple logo on step 2. c) press the Volume Down Button (while still pressing the power button) and DO NOT RELEASE THESE 2 BUTTONS UNTIL YOU SEE THE CAPLE CONNECT TO COMPUTER ICON on a black screen (this is the sign that you've successfully entered the DFU mode)
3. Now open Finder on Mac, select your iPhone (left menu Locations) and choose to "Restore iPhone" (if there is a pop-up that appears on your Mac asking to connect your iPhone -> select Allow -> select Restore option) - do not choose "Update"
4. Stay connected after the phone has been restored. Make sure you pass the Hello screen before you can unplug it.
* DFU mode:
* Restore iPhone from Finder on Mac:
* Successfully restored: