203114 files and directories currently installed.) Mint-plasma /media/cdrom/pool/main/g/glibc $ sudo dpkg -i libc6-dev_2.23-0ubuntu7_b Processing triggers for man-db (2.7.5-1). Preparing to unpack libc-dev-bin_2.23-0ubuntu7_b. 203101 files and directories currently installed.) Selecting previously unselected package libc-dev-bin. Mint-plasma /media/cdrom/pool/main/g/glibc $ sudo dpkg -i libc-dev-bin_2.23-0ubuntu7_b Here's the solution for anyone who happens to have the same problem. That wasn't quite the answer, but it was close enough for me to figure it out. I'm willing to admit that I may have gone down the wrong rabbit hole, but I feel like I *should* have everything I need on the USB stick since it was SO easy to get the Live session on Wifi. This macbook doesn't have a hard ethernet port either.
Now when I try to install bcmwl-kernel-source from the command line, it tried to upgrade lib6c (and a few other packages) that aren't on the live stick. This seemed to work and I was able to add the "cd" to apt with apt-cdrom. I figured I would outsmart it and I mounted the USB stick on /media/cdrom. I think this is because KDE mounts the USB stick on /media/user/VOLUMENAME I got a similar message when doing apt-get install bcmwl-kernel-source from the CLI. I got an error about not being able to find the Release file on deb cdrom. I open Driver Manager and choose the broadcom driver, but it fails to install it from the USB stick. When I install to the hard drive and reboot, I don't have Wifi (as expected). After I boot into the live session I can start Driver Manager and easily install the Broadcom driver to get Wifi working.