diff --git a/assets/android.lua b/assets/android.lua
index 5370b37a7..7bbec8b69 100644
--- a/assets/android.lua
+++ b/assets/android.lua
@@ -1047,7 +1047,7 @@ function JNI:callBooleanMethod(object, method, signature, ...)
     local clazz = self.env[0].GetObjectClass(self.env, object)
     local methodID = self.env[0].GetMethodID(self.env, clazz, method, signature)
     self.env[0].DeleteLocalRef(self.env, clazz)
-    return self.env[0].callBooleanMethod(self.env, object, methodID, ...)
+    return self.env[0].CallBooleanMethod(self.env, object, methodID, ...)
 end
 
 function JNI:callStaticBooleanMethod(class, method, signature, ...)
@@ -1363,10 +1363,10 @@ local function run(android_app_state)
             local fullscreen = JNI:callIntMethod(
                 android.app.activity.clazz,
                 "isFullscreen",
-                "()Z"
+                "()I"
             )
             android.LOGI("is fullscreen =", fullscreen)
-            return fullscreen
+            return fullscreen == 1
         end)
     end
     android.setFullscreen = function(fullscreen)
@@ -1398,10 +1398,10 @@ local function run(android_app_state)
             local isWifiEnabled = JNI:callIntMethod(
                 android.app.activity.clazz,
                 "isWifiEnabled",
-                "()Z"
+                "()I"
             )
             android.LOGI("is WifiEnabled =", isWifiEnabled)
-            return isWifiEnabled
+            return isWifiEnabled == 1
         end)
     end
 
diff --git a/src/org/koreader/launcher/MainActivity.java b/src/org/koreader/launcher/MainActivity.java
index 9620568b0..adb37d2da 100644
--- a/src/org/koreader/launcher/MainActivity.java
+++ b/src/org/koreader/launcher/MainActivity.java
@@ -158,8 +158,8 @@ public void run() {
         });
     }
 
-    public boolean isFullscreen() {
-    	return (getWindow().getAttributes().flags & WindowManager.LayoutParams.FLAG_FULLSCREEN) != 0;
+    public int isFullscreen() {
+    	return ((getWindow().getAttributes().flags & WindowManager.LayoutParams.FLAG_FULLSCREEN) != 0) ? 1: 0;
     }
 
 
@@ -167,8 +167,8 @@ public void setWifiEnabled(final boolean enabled) {
         this.getWifiManager().setWifiEnabled(enabled);
     }
 
-    public boolean isWifiEnabled() {
-        return this.getWifiManager().isWifiEnabled();
+    public int isWifiEnabled() {
+        return this.getWifiManager().isWifiEnabled() ? 1 : 0;
     }
 
     private WifiManager getWifiManager() {