Open android browser and go to url

Hi, I’m using Robotframework AppiumLibrary to automate android apps.

I’m trying to open a browser in a real device and go to an url.

This is what I do:

call Open Application keyword pasing the following arguments:
platformName: Android
platformVersion: 4.4
deviceName: ZH8008A87D
browserName: Firefox
androidPackage: org.mozilla.firefox
appActivity: org.mozilla.firefox.App
appiumVersion: 1.4.11

This step works fine as I can see the firefox app screen in the device.

Then I call Go To Url keyword passing an url ( for example) as parameter.

But when I do that, I’m getting this error:
WebDriverException: Message: Not yet implemented. Please help us:

Thanks for the help!