Hi, all. I'll try to keep this brief. Also, my apologies, I'm writing this on the Win10 partition on the same machine I'm trying to install on and therefore don't have access to the logs. Some of this will seem fuzzy.

Trying to dual boot Neon (either LTS or Daily) on a machine with WIndows 10 and UEFI. Until this afternoon this machine successfully dual booted in this configuration with Ubuntu 16.04.

I get all the way through the Neon installer (or at least I think I do) and at the end get an error that we can't install grub to /target/. That error seems pretty common and there are lots of threads dedicated on how to fix it.

When working my way through the logs I see errors complaining that system can't download a particular .deb that grub seems to want. This problem seems confirmed when I try to manually install grub.

This brings me back to the network. Those network drivers I need to activate the Broadcom wireless don't get installed/configured until after first boot. And I can't get to first boot because grub fails to install because it can't download dependencies. It seems I'm in a bit of a loop.

Hopefully this makes sense. Can anyone help?

Hello,
I'm unclear on why the installation disk needs internet access unless it is a net installation installer. If it is a net installation installer then you will probably need to plug the laptop to the router with an ethernet cable until you install the firmware for the wireless adapter. I wasn't aware that KDE neon had a net installer though. Which version of KDE neon are you trying to install?

You need internet access when installing on an UEFI system

https://bugs.kde.org/show_bug.cgi?id=380470