Image, loading *.pkm file(ETC1) issue

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Hi,
I'was trying to test the new features from Qt 5.10 and 5.11, and I have a problem with the loading of Image from .pkm file.
I used for my test a png, I conveted it into pkm(etc1) with Mali Texture Compression Tool (v4.3.0) and I test with to "etc1tool".
I can encode and decode from each other without any problem. (png->pkm with one and pkm->png with the other one for example).
So it's seems their is no problem with the generated pkm files.
But when I trying to load one in the QML with Image, It display a black image with the expected size.
This is my code to test it :

import QtQuick 2.11
import QtQuick.Window 2.11

Window {
    id: window
    visible: true
    width: 1000
    height: 1000
    title: qsTr("Hello World")
    color : "black"

    Rectangle{
        color : "darkgray"
        x:0
        y:0
        width:grid.width +20
        height: grid.height + 20
        Grid {
            x:10
            y:10
            id:grid
            columns: 3

            horizontalItemAlignment: Grid.AlignHCenter
            verticalItemAlignment: Grid.AlignVCenter

            spacing: 10

            Text{text : " "; font.pixelSize: 20}
            Text{text : "Normal"; font.pixelSize: 20}
            Text{text : "Pre-alpha"; font.pixelSize: 20}

            Text{text : ".png"; font.pixelSize: 20}
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon.png"; sourceSize.width: 200; sourceSize.height: 200 }
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon_pre.png"; sourceSize.width: 200; sourceSize.height: 200 }

            Text{text : "ETC1 (.pkm)"; font.pixelSize: 20}
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon.pkm"}
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon_pre.pkm"}

            Text{text : "auto pick"; font.pixelSize: 20}
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon"}
            Image { source: "file:///" + applicationDirPath + "/../../imagine_style_test/assets/fuel_gauge/qt_icon_pre"}
        }
    }
}

And finally what is displayed :

I test the compilation under linux and windows(mingw) against Qt 5.10 and 5.11.1 : same results.

Can someone help me ?
Thanks