UPDATE: V3.18 addresses many of these issues
Read on for the old way …
Yep that easy!
Hmm. One more thing to try. Some updates have been having trouble with free space, and since your page is hosed anyway, we can try deleting it.
Try this (it will nuke the main web app file)
curl 'http://192.168.4.1/delete?path=/index.html.gz'
Then if you load the page you shouldn’t get the cube spinner at all. Then try applying the update again.