I'm having a dickens of a time overriding entity.tpl.php to create custom themes for my entities.
I am using ECK and Inline Entity Form. I've created entity
section with bundle
masthead. I've linked this to a node.
In a subtheme of the bootstrap theme, I then try to create a custom theme for this entity in a file called
entity--section--masthead.tpl.php (note: I've also tried
section--masthead.tpl.php and all sorts of permutations). Clear Cache. Nothing.
The only documentation is a few years old, and one of the most recent comments says this SHOULD work without the need for various hooks.