Yes, you have to sideload. See attached apk.
You can use any number of apps out there that will prevent FTV from sleeping. I use the "RedEye Stay Awake", free version.
The direct link in Google Play Store is https://play.google.com/store/apps/details?id=com.binarymagi.redeye.free&hl=en
When i side-loaded the latest 7.0.99 from apkmirror.com it said failed older SDK, but i'll try the version you posted.
---------- Post added at 06:57 PM ---------- Previous post was at 06:48 PM ----------
I just side-loaded your version and vo...
I installed HBO GO just now (first install) on my FTV through Amazon. The apk is available at:
App version is 2.7.06
Edit: I don't have HBO subscription, so cannot activate and watch something for test...
Has this bug been fixed yet?
I am not sure. I stopped using StickMount a long time back (probably around the time of my OP) as it never worked correctly. E.g. it used to give a bogus message that my USB was mounted when there was no USB connect...