I'm having trouble getting my Posboxes to work with my remote Odoo v10 server with Nginx and SSL.

I have tried configuring Nginx to send request to /pos/ over http. This results in a Mixed Content error in Safari and Chrome.
As I am using iPads, I cannot make Safari ignore this. This is also the result when I try to serve the /pos/ directory over https.
This results in the browser not being able to connect to the Posbox.

I've read and tried the solutions in these GitHub issues, with no success:

https://github.com/odoo/odoo/issues/2031
https://github.com/odoo/odoo/issues/3156

Does anyone have a working Nginx config example for use with Odoo 10?