I was able to restore it using the the following command:
dd if=/dev/zero/ of=/dev/block/platform/msm_sdcc.1/by-name/fota
dd if=/dev/zero/ of=/dev/block/platform/msm_sdcc.1/by-name/misc
That brought it back to stock, and thinking everything was ok, I tried to update again. Now the above commands will not work, possibly because I hadn't rooted and turned on USB debugging yet. When I select reboot from the TWRP menu, I get a message asking if I want to root with SuperuserUS, but it doesn't work.
I've tried everything, including all the LG flash tools, and nothing works.Because I've got the international version, but I'm with Telus, I can't find/select the proper stock ROM.
I'm really hoping I can avoid a $600 brick.