The custom thermostat card in lovelace-ui will not load in the fully kiosk browser on a Fire 8. I get a big redbox that says Custom element doesn’t exist: thermostat-card.
This only happens in the fully kiosk browser. It renders fine in other browsers. It also works fine on the Silk browser on the fire tablet. I have other custom cards that work fine within fully kiosk, such as monster-card, guage-card, and tracker-card.
Probably because this is using module and loads an extra JS. Currently development is going slower because I’m searching for alternatives exactly for this - to avoid needing multiple files by using either stenciljs or webpack. So far I hit a few problems, but eventually will get there.
Has there been any progress with this?
I’m trying to use fully kiosk browser with lovelace and anything using a custom element won’t load - and that is pretty much most of my interface!
As the initial poster - the page works fine using chrome on my Kindle.
I may of course be approaching this all wrong - is there a better way to get a full on kiosk mode with lovelace on a tablet?
I’ve attached a screenshot to illustrate.
Bump. I’m having the same problem. Anyone have any suggestions here? 
Same here, this renders my Amazon Fire Tablets setup useless
I wonder what the actual problem is here. In the documentation it says:
Custom cards are treated the same as built-in cards
But that doesn’t appear to be true, since built-in cards work well in my old webview version. What is the actual difference between custom cards and build-in cards? Both are custom elements aren’t they?
If it is an compatability issue with a new javascript features, maybe we can solve this with a polyfill?
Any developers here who can shed some light on this?
Just to amend my previous post: It is not just custom cards. the new lovalace thermostat card in 0.81.4 doesn’t work either in my old Fire Tablet webview.
Ah, that’s a shame. I was hoping with HA 0.81 officially adding thermostat and button cards would mean those cards would work in Fully Kiosk with a Fire tablet, but I guess not.
The issue is definitely the old webview on Amazon Fire tablets. I have an Amazon Fire HD8 and an old LG G Pad running Android 5.0–both run Fully Kiosk Browser and only the G Pad can load custom cards like the thermostat and button cards properly. Using Google Chrome on the Fire tablet fixes the problem, but uses too much screen real estate.
Well, correction. It seems, I should have cleared my cache before posting. 
The new thermostat card, as well as the new button cards, work flawlessly in old webview.
It remains a problem with custom cards. I will try to figure out, what the difference actually is. This bugs me.
Is there any solution? Still facing the same problem.
I appear to be running into this as well, on a new Fire HD 10 tablet.
Just to comment here on what is happening.
Fullykiosk does not support lit-html on Fire tablets, which is what a lot of Lovelace uses. This is especially true for custom cards.
Using the built-in Chrome browser on the Fire tablets should work with lit-html, because it is using a different (and more updated) web engine. This obviously isn’t ideal.
So from my understanding, unless there’s an update to Fullykiosk, these sort of cards just won’t work on Fire tablets, which is a real shame.
Changing type from module to js solved it for me.
https://github.com/home-assistant/home-assistant/issues/18420
where are you editing this? Thanks (Im a noob)
Did you ever get an answer?
