Small changes

src/core/session.ts

                 // update internals
                 this._updateStats.update();
                 this._frameReady = true;
-            }).catch((err: any) => {
+            }).catch(err => {
                 // log error
                 Utils.error('Tracking error: ' + err.toString(), err);
 
-                // throw WebGL errors
-                if(err.name == 'GLError' || (typeof err.cause == 'object' && err.cause.name == 'GLError')) {
+                // handle WebGL errors
+                const cause = (err as any).cause;
+                if(err.name == 'GLError') {
                     alert(err.message); // fatal error?
+                    alert(Utils.deviceInfo()); // display useful info
+                    throw err;
+                }
+                else if(typeof cause == 'object' && cause.name == 'GLError') {
+                    alert(err.message);
+                    alert(cause.message);
+                    alert(Utils.deviceInfo());
                     throw err;
                 }
             });

src/utils/utils.ts

      */
     static deviceInfo(): string
     {
-        return JSON.stringify({
+        return 'Device info: ' + JSON.stringify({
             isIOS: Utils.isIOS(),
             isWebKit: Utils.isWebKit(),
             renderer: Speedy.Platform.renderer,
             vendor: Speedy.Platform.vendor,
-            screen: [screen.width, screen.height].toString(),
+            screen: [screen.width, screen.height].join('x'),
+            platform: [navigator.platform, navigator.vendor].join('; '),
             userAgent: navigator.userAgent,
-            platform: [Utils.platformString(), navigator.platform, navigator.vendor],
-        }, null, 4);
+            userAgentData: (navigator as any).userAgentData || null,
+        }, null, 2);
     }
 }