Zorin core upgrade/reinstall booting to black screen

[JoshOfCourse]

On this other topic I made, for the problem with my friend, @Aravisian replied with this, when we figured out it was the Kernel:

@Aravisian

In your case, reinstalling Zorin OS from the .iso, then setting your kernel to default boot to the Working Kernel:

@Aravisian

You may need to use an earlier kernel than the current kernel used by Zorin. This method allows you to set the kernel that you will boot into by default.

To set the new kernel to default:

Boot into the kernel you wish to be Saved.
Open terminal and run:

sudo nano /etc/default/grub

Change GRUB_DEFAULT=0 to GRUB_DEFAULT=saved
Hit enter to drop down a line.
Add GRUB_SAVEDEFAULT=true
ctrl+x to exit, then the y key to say yes to save, then the enter key to save as current configuration.

Run

sudo update-grub

to make the changes take effect.

Remember: if you boot into the later kernel for some reason (testing or whatever), that will become the new Saved Kernel at next reboot. So you must hit tab or esc at the M.B. splash screen to get to Advanced Options for Zorin and reselect the preferred kernel and boot into it. Once done, it will then remain as the Saved Default.

This way you can safely install updates.

"That way you can safely install updates", and change your kernel. Haven't had time to try it but probably works.