I was getting the following error
Ubuntu 16.04 graphics failure: (EE) error, (NI) not implemented; (EE) VESA(0): V_BIOS address 0x0 out of range
After following the uninstall part of the solution in this answer Ubuntu 16.04 graphics failure: (EE) error, (NI) not implemented; (EE) VESA(0): V_BIOS address 0x0 out of range , I can not boot even using recovery mode because I get Target filesystem doesnt have requested /sbin/init. How could I install the needed packages?
You should at least be able to fall back into a shell with Ctrl+Alt+F2, or perhaps with a grub command (you'd have to google that). If you can't, this might not be worth pursuing.
I think that what you would have to do is to use a live-USB to chroot into the system, then start repairing the system.
For information on how to use chroot I would look at the Arch-Wiki.
If you do get into a shell and you simply need to rectify having removed Xorg, you would have to reinstall that, obviously, and I'm not sure if you would also have to reinstall GDM and Gnome3.
Those links will walk through how to install it all, but in all honesty, having been through this stuff before, it's almost always quicker to just wipe and reinstall. I know that sounds drastic, but it takes like 20 minutes of zero effort to reinstall, particularly with a fast internet connection.
I personally try to have my partitions set up so that I can reinstall at the drop of a hat with no data loss, because I simply don't have the time to try and fix my OS, which usually seems like it will take 5 minutes but takes 5 hours :/ .
