The LS660ZV6_01.zip update has been dogging me for about a month on my Virgin Mobile LG Tribute phone. I couldn't install it. No matter what I did, there was "insufficient space" to do so. I finally got the update installed, and I will share my not-so-secret discovery with you.
tl;dr: You need 550 MB of free space to install the ZV6 update on the LG Tribute. Start deleting app data and full apps until you get there. Then try to install the update that has been dogging you and eating up your data for at least a month if not longer. It should work.
Even though the LS660ZV6_01.zip update is supposed to be "only" 73 MB in size, the most internal memory I've been able to free up by clearing out app data and cache was 300 MB. And the update still won't install. There is still "insufficient space" to cram this supposedly 73 MB update on my LG Tribute's 4 GB of internal memory.
This post is here more so I don't lose track of this extremely detailed tutorial on how to deal with iOS 7 devices under Linux, especially Fedora.
(Because friends don't let friends use iTunes)