diff --git a/xwords4/android/XWords4/build.xml b/xwords4/android/XWords4/build.xml
index b1d8ad988..d1536010c 100644
--- a/xwords4/android/XWords4/build.xml
+++ b/xwords4/android/XWords4/build.xml
@@ -61,6 +61,7 @@
         </exec>
         <exec dir="." executable="../scripts/gen_gcmid.sh"
               output="src/org/eehouse/android/xw4/GCMConsts.java"
+              logError="true"
               />
         <exec dir=".." executable="./scripts/genvers.sh" output="ant_out.txt">
           <arg value="XWords4"/>
diff --git a/xwords4/android/XWords4/src/org/eehouse/android/xw4/GCMIntentService.java b/xwords4/android/XWords4/src/org/eehouse/android/xw4/GCMIntentService.java
index 2ab40f4bc..1fc22e503 100644
--- a/xwords4/android/XWords4/src/org/eehouse/android/xw4/GCMIntentService.java
+++ b/xwords4/android/XWords4/src/org/eehouse/android/xw4/GCMIntentService.java
@@ -74,7 +74,7 @@ public class GCMIntentService extends GCMBaseIntentService {
     public static void init( Application app )
     {
         int sdkVersion = Integer.valueOf( android.os.Build.VERSION.SDK );
-        if ( 8 <= sdkVersion ) {
+        if ( 8 <= sdkVersion && 0 < GCMConsts.SENDER_ID.length() ) {
             try {
                 GCMRegistrar.checkDevice( app );
                 // GCMRegistrar.checkManifest( app );
diff --git a/xwords4/android/scripts/gen_gcmid.sh b/xwords4/android/scripts/gen_gcmid.sh
index 9ca58833a..75bbb2089 100755
--- a/xwords4/android/scripts/gen_gcmid.sh
+++ b/xwords4/android/scripts/gen_gcmid.sh
@@ -1,8 +1,9 @@
 #!/bin/sh
 
+set -e -u
+
 if [ -z "$GCM_SENDER_ID" ]; then
-    echo "GCM_SENDER_ID not in env"
-    exit 1
+    echo "GCM_SENDER_ID empty; GCM use will be disabled" >&2
 fi
 
 cat <<EOF