Update README.md (#202)

Documented a workaround to communicate with Home Assistant using HTTP.

Author: philipabbey

README.md

@@ -11,7 +11,9 @@ The application is designed around a simple scrollable menu where menu items hav
 **The intended audience for this application are those comfortable with configuring a Home Assistant** (e.g. editing the YAML configuration files) and debugging why URLs don't work. It does not require programming skills, but the menu is configured via JSON which feels like "coding". If you are not comfortable with this relatively low level of configuration, you may like to try other Garmin applications instead.
 
 > [!IMPORTANT]
-> It is important to note that your Home Assistant instance will need to be accessible via HTTPS with public SSL or all requests from the Garmin will not work. This cannot be a self-signed certificate, it must be a public certificate. You can get one for free from [Let's Encrypt](https://letsencrypt.org/) or you can pay for [Home Assistant cloud](https://www.nabucasa.com/). (You can install a local [Nginx proxy server](https://my.home-assistant.io/redirect/supervisor_addon/?addon=a0d7b954_nginxproxymanager) to manage Let's Encrypt certificates.)
+> The Garmin SDK allows HTTP requests only to a limited number of domains specified in their app. Therefore, for your Garmin to communicate with your Home Assistant instance, your Home Assistant instance must be accessible via HTTPS (with a public certificate!) or through a local DNS server that overrides one of the whitelisted domains to communicate using HTTP.
+> To make your Home Assistant instance accessible via HTTPS, you will need a public certificate. You can get one for free from [Let's Encrypt](https://letsencrypt.org/) or you can pay for [Home Assistant cloud](https://www.nabucasa.com/). (You can install a local [Nginx proxy server](https://my.home-assistant.io/redirect/supervisor_addon/?addon=a0d7b954_nginxproxymanager) to manage Let's Encrypt certificates.)
+> If you use a local DNS server (like [Pi-Hole](https://pi-hole.net/)), you can create a local DNS record for the domain `garmincdn.com` (which is allowed for HTTP in the Garmin SDK) and map it to your Home Assistant instance's IP. You can find additional workarounds for HTTP request restrictions in the Garmin SDK [here](https://www.instructables.com/About-Communication-Between-Garmin-SDK-and-a-Raspb/).
 
 **If you are struggling with getting the application to work, please consult the [trouble shooting](TroubleShooting.md#menu-configuration-url) guide first.**
 
@@ -326,8 +328,8 @@ The `id` attribute values are taken from the same names used in [`strings.xml`](
 
 6. We are unable to support Edge 540, Edge 840 and Edge 1050 devices at this time. The simulation of these devices has two unexpected errors when toggling or executing taps. We get both `Communications.NETWORK_RESPONSE_OUT_OF_MEMORY` and `Communications.BLE_QUEUE_FULL` even though the memory usage is about 6% of the available RAM. Based on a lead from user @Petucky, both devices are being re-enabled as testing on a real Edge 840 device has proven successful, however we remain unable to support either devices until the simulator is fixed.
 
-7. We are unable to support HTTP without HTTPS. This is a limitation placed upon us by the Connect IQ API which for security reasons refuses to work with HTTP requests. There is nothing developers can do about this limitation. You will have to put an HTTPS proxy in front of your local Home Assistant to work with this application. See the [Trouble Shooting](TroubleShooting.md#do-it-yourself-setup) guide for an example setup.  We would appreciate it if users did not leave poor reviews for the lack of this feature which is beyond our control to fix.
+7. We are unable to support HTTP natively (without the workaround specified earlier). This is a limitation placed upon us by the Connect IQ API which for security reasons refuses to work with HTTP requests. There is nothing developers can do about this limitation. See the [Trouble Shooting](TroubleShooting.md#do-it-yourself-setup) guide for an example setup. We would appreciate it if users did not leave poor reviews for the lack of this feature which is beyond our control to fix.
 
 8. There is a [bug in Garmin Express so that when you use that software to amend the application's settings](https://github.com/house-of-abbey/GarminHomeAssistant/issues/194), the page appears in a random language not of your choice. I would like to thank user [heviiguy](https://github.com/heviiguy) for his work researching the issue, leading to these references that indicate the authors of Garmin Home Assistant cannot resolve this issue as its a bug in Garmin Express that Garmin are refusing to believe exists! See these pages for details:
    - [Garmin Express - Wrong Language](https://forums.garmin.com/developer/connect-iq/i/bug-reports/garmin-express---wrong-language)
-   - [Incorrect language displayed for custom data fields](https://forums.garmin.com/developer/connect-iq/f/discussion/388137/incorrect-language-displayed-for-custom-data-fields)
+   - [Incorrect language displayed for custom data fields](https://forums.garmin.com/developer/connect-iq/f/discussion/388137/incorrect-language-displayed-for-custom-data-fields)