diff --git a/xwords4/android/jni/utilwrapper.c b/xwords4/android/jni/utilwrapper.c
index c8aece2eb..e5ded2a1c 100644
--- a/xwords4/android/jni/utilwrapper.c
+++ b/xwords4/android/jni/utilwrapper.c
@@ -27,6 +27,7 @@
 #include "andutils.h"
 #include "paths.h"
 #include "LocalizedStrIncludes.h"
+#include "dbgutil.h"
 
 #define MAX_QUANTITY_STRS 4
 
@@ -909,6 +910,7 @@ makeUtil( MPFORMAL EnvThreadInfo* ti, jobject jutil, CurGameInfo* gi,
     SET_PROC(getDevUtilCtxt);
 
 #undef SET_PROC
+    assertTableFull( vtable, sizeof(*vtable), "util" );
     return (XW_UtilCtxt*)util;
 } /* makeUtil */
 
@@ -965,6 +967,9 @@ makeDUtil( MPFORMAL EnvThreadInfo* ti, jobject jdutil, VTableMgr* vtMgr,
     SET_DPROC(notifyPause);
     SET_DPROC(onDupTimerChanged);
 
+#undef SET_DPROC
+
+    assertTableFull( vtable, sizeof(*vtable), "dutil" );
     return &dutil->dutil;
 }
 
diff --git a/xwords4/common/dbgutil.c b/xwords4/common/dbgutil.c
index 6aca6f1c3..f561d92ab 100644
--- a/xwords4/common/dbgutil.c
+++ b/xwords4/common/dbgutil.c
@@ -126,5 +126,24 @@ devIDTypeToStr(DevIDType typ)
 }
 
 #undef CASESTR
+typedef void (*ProcPtr)();
+void
+assertTableFull( void* table, size_t sizeInBytes, const XP_UCHAR* tableName )
+{
+    if ( 0 != sizeInBytes % sizeof(ProcPtr) ) {
+        XP_LOGFF( "bad call? vtable size: %zu; proc ptr size: %zu", sizeInBytes, sizeof(ProcPtr) );
+        XP_ASSERT( 0 );
+    }
 
-#endif
+    ProcPtr* proc = (ProcPtr*)table;
+    int count = sizeInBytes / sizeof(ProcPtr);
+    for ( int ii = 0; ii < count; ++ii ) {
+        if ( !*proc ) {
+            XP_LOGFF( "%s.vtable[%d] missing", tableName, ii );
+            XP_ASSERT( 0 );
+        }
+        ++proc;
+    }
+}
+
+#endif  /* DEBUG */
diff --git a/xwords4/common/dbgutil.h b/xwords4/common/dbgutil.h
index a5ca87dcf..692de8758 100644
--- a/xwords4/common/dbgutil.h
+++ b/xwords4/common/dbgutil.h
@@ -53,4 +53,10 @@ const char* devIDTypeToStr(DevIDType typ);
 #  define SET_DIRTY( ptr )
 # endif
 
+# ifdef DEBUG
+void assertTableFull( void* table, size_t sizeInBytes, const XP_UCHAR* tableName );
+# else
+#  define assertTableFull( table, sizeInBytes, tableName )
+# endif
+
 #endif
diff --git a/xwords4/linux/cursesboard.c b/xwords4/linux/cursesboard.c
index 66784412a..3e06bda4f 100644
--- a/xwords4/linux/cursesboard.c
+++ b/xwords4/linux/cursesboard.c
@@ -34,6 +34,7 @@
 #include "gsrcwrap.h"
 #include "linuxsms.h"
 #include "strutils.h"
+#include "dbgutil.h"
 
 typedef struct CursesBoardState {
     CursesAppGlobals* aGlobals;
@@ -1128,7 +1129,7 @@ setupCursesUtilCallbacks( CursesBoardGlobals* bGlobals, XW_UtilCtxt* util )
 #endif
 #undef SET_PROC
 
-    assertUtilCallbacksSet( util );
+    assertTableFull( util->vtable, sizeof(*util->vtable), "curses util" );
 } /* setupCursesUtilCallbacks */
 
 static bool
diff --git a/xwords4/linux/gtkboard.c b/xwords4/linux/gtkboard.c
index 68af06791..d7c6677df 100644
--- a/xwords4/linux/gtkboard.c
+++ b/xwords4/linux/gtkboard.c
@@ -2232,7 +2232,7 @@ setupGtkUtilCallbacks( GtkGameGlobals* globals, XW_UtilCtxt* util )
 
 #undef SET_PROC
 
-    assertUtilCallbacksSet( util );
+    assertTableFull( util->vtable, sizeof(*util->vtable), "gtk util" );
 } /* setupGtkUtilCallbacks */
 
 #ifndef XWFEATURE_STANDALONE_ONLY
diff --git a/xwords4/linux/linuxmain.c b/xwords4/linux/linuxmain.c
index b954f0cc1..aaf34f9f5 100644
--- a/xwords4/linux/linuxmain.c
+++ b/xwords4/linux/linuxmain.c
@@ -2388,20 +2388,6 @@ setupLinuxUtilCallbacks( XW_UtilCtxt* util )
 #undef SET_PROC
 }
 
-void
-assertUtilCallbacksSet( XW_UtilCtxt* util )
-{
-    XWStreamCtxt* (**proc)(XW_UtilCtxt*, XP_PlayerAddr ) =
-        &util->vtable->m_util_makeStreamFromAddr;
-    for ( int ii = 0; ii < sizeof(*util->vtable)/sizeof(*proc); ++ii ) {
-        if ( !*proc ) {
-            XP_LOGF( "%s(): null ptr at index %d", __func__, ii );
-            XP_ASSERT( 0 );
-        }
-        ++proc;
-    }
-}
-
 void
 assertDrawCallbacksSet( const DrawCtxVTable* vtable )
 {