looked at unity's AsyncOperation.progress which is apparently terribly broken so the download ProgressBar now ignores negative progress changes.

Assets/RothenburgAR/Scripts/Updater/UpdaterBehaviour.cs

@@ -208,8 +208,6 @@ namespace RothenburgAR.Updater
 
         private void UpdateMedia(Exhibit exhibit)
         {
-            //TODO check existing file for creation/alteration date to see if download is necessary
-
             var mediaIDs = exhibit.Pois.Select(p => p.MediaId).Except(new List<string> { null }).ToList();
 
             foreach (var mediaId in mediaIDs)
@@ -217,7 +215,7 @@ namespace RothenburgAR.Updater
                 var path = PathHelper.CombinePaths(PathHelper.MediaPath, mediaId);
                 var filepath = Path.Combine(path, "media.zip");
 
-                //TODO cancel download if unnecessary
+                //TODO cancel download if unnecessary, how to check if unnecessary?
                 if (File.Exists(filepath)) continue;
 
                 // create file and dir if nonexistent
@@ -286,7 +284,12 @@ namespace RothenburgAR.Updater
 
                 downloadProgress /= httpHandlers.Count;
 
-                ProgressBar.value = downloadProgress;
+                // operation.progress is bugged and goes all over the place:
+                //      jumps from 0 to 1 and back despite not being done 
+                //      steadily increases from 0,5 to 0,99 and resets to 0,5 multiple times (5-15x) during a single download
+
+                // update progress bar and ignore all negative changes
+                ProgressBar.value = ProgressBar.value < downloadProgress ? downloadProgress : ProgressBar.value;
             }
 
             // Continue to Main Scene after all downloads are done and this.afterDownloadWaitTime seconds have passed without any new downloads triggering.

Assets/updaterScene.unity

@@ -351,7 +351,7 @@ MonoBehaviour:
     m_SelectOnRight: {fileID: 0}
   m_Transition: 1
   m_Colors:
-    m_NormalColor: {r: 0.011764707, g: 0.6627451, b: 0.9568628, a: 1}
+    m_NormalColor: {r: 1, g: 1, b: 1, a: 1}
     m_HighlightedColor: {r: 0.9607843, g: 0.9607843, b: 0.9607843, a: 1}
     m_PressedColor: {r: 0.78431374, g: 0.78431374, b: 0.78431374, a: 1}
     m_DisabledColor: {r: 0.78431374, g: 0.78431374, b: 0.78431374, a: 0.5019608}
@@ -395,7 +395,7 @@ MonoBehaviour:
   m_Script: {fileID: -765806418, guid: f70555f144d8491a825f0804e09c671c, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  m_Material: {fileID: 0}
+  m_Material: {fileID: 2100000, guid: bb09bb844e7d9f84da8e12b7ef465ac5, type: 2}
   m_Color: {r: 1, g: 1, b: 1, a: 1}
   m_RaycastTarget: 1
   m_OnCullStateChanged:
@@ -1129,8 +1129,8 @@ MonoBehaviour:
   m_fontMaterials: []
   m_fontColor32:
     serializedVersion: 2
-    rgba: 4279308561
+    rgba: 4294967295
-  m_fontColor: {r: 0.06666667, g: 0.06666667, b: 0.06666667, a: 1}
+  m_fontColor: {r: 1, g: 1, b: 1, a: 1}
   m_enableVertexGradient: 0
   m_fontColorGradient:
     topLeft: {r: 1, g: 1, b: 1, a: 1}
@@ -1424,11 +1424,11 @@ MonoBehaviour:
     lineCount: 3
     pageCount: 1
     materialCount: 1
-  m_havePropertiesChanged: 1
+  m_havePropertiesChanged: 0
   m_isUsingLegacyAnimationComponent: 0
   m_isVolumetricText: 0
   m_spriteAnimator: {fileID: 0}
-  m_isInputParsingRequired: 1
+  m_isInputParsingRequired: 0
   m_inputSource: 0
   m_hasFontAssetChanged: 0
   m_subTextObjects:
@@ -1589,7 +1589,7 @@ MonoBehaviour:
     m_SelectOnRight: {fileID: 0}
   m_Transition: 1
   m_Colors:
-    m_NormalColor: {r: 0.011764707, g: 0.6627451, b: 0.9568628, a: 1}
+    m_NormalColor: {r: 1, g: 1, b: 1, a: 1}
     m_HighlightedColor: {r: 0.9607843, g: 0.9607843, b: 0.9607843, a: 1}
     m_PressedColor: {r: 0.78431374, g: 0.78431374, b: 0.78431374, a: 1}
     m_DisabledColor: {r: 0.78431374, g: 0.78431374, b: 0.78431374, a: 0.5019608}
@@ -1633,7 +1633,7 @@ MonoBehaviour:
   m_Script: {fileID: -765806418, guid: f70555f144d8491a825f0804e09c671c, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  m_Material: {fileID: 0}
+  m_Material: {fileID: 2100000, guid: bb09bb844e7d9f84da8e12b7ef465ac5, type: 2}
   m_Color: {r: 1, g: 1, b: 1, a: 1}
   m_RaycastTarget: 1
   m_OnCullStateChanged:
@@ -1702,8 +1702,8 @@ MonoBehaviour:
   m_Script: {fileID: -765806418, guid: f70555f144d8491a825f0804e09c671c, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  m_Material: {fileID: 0}
+  m_Material: {fileID: 2100000, guid: bb09bb844e7d9f84da8e12b7ef465ac5, type: 2}
-  m_Color: {r: 0.011764706, g: 0.6627451, b: 0.95686275, a: 1}
+  m_Color: {r: 1, g: 1, b: 1, a: 1}
   m_RaycastTarget: 1
   m_OnCullStateChanged:
     m_PersistentCalls:
@@ -1788,8 +1788,8 @@ MonoBehaviour:
   m_fontMaterials: []
   m_fontColor32:
     serializedVersion: 2
-    rgba: 4279308561
+    rgba: 4294967295
-  m_fontColor: {r: 0.06666667, g: 0.06666667, b: 0.06666667, a: 1}
+  m_fontColor: {r: 1, g: 1, b: 1, a: 1}
   m_enableVertexGradient: 0
   m_fontColorGradient:
     topLeft: {r: 1, g: 1, b: 1, a: 1}
@@ -2338,8 +2338,8 @@ MonoBehaviour:
   m_fontMaterials: []
   m_fontColor32:
     serializedVersion: 2
-    rgba: 4279308561
+    rgba: 4294967295
-  m_fontColor: {r: 0.06666667, g: 0.06666667, b: 0.06666667, a: 1}
+  m_fontColor: {r: 1, g: 1, b: 1, a: 1}
   m_enableVertexGradient: 0
   m_fontColorGradient:
     topLeft: {r: 1, g: 1, b: 1, a: 1}
@@ -2404,11 +2404,11 @@ MonoBehaviour:
     lineCount: 1
     pageCount: 1
     materialCount: 1
-  m_havePropertiesChanged: 1
+  m_havePropertiesChanged: 0
   m_isUsingLegacyAnimationComponent: 0
   m_isVolumetricText: 0
   m_spriteAnimator: {fileID: 0}
-  m_isInputParsingRequired: 1
+  m_isInputParsingRequired: 0
   m_inputSource: 0
   m_hasFontAssetChanged: 0
   m_subTextObjects: