diff --git a/src/joystick/virtual/SDL_virtualjoystick.c b/src/joystick/virtual/SDL_virtualjoystick.c
index 2b1c1a681..64d032f18 100644
--- a/src/joystick/virtual/SDL_virtualjoystick.c
+++ b/src/joystick/virtual/SDL_virtualjoystick.c
@@ -160,7 +160,7 @@ SDL_JoystickAttachVirtualInner(const SDL_VirtualJoystickDesc *desc)
         int i, axis;
 
         if (hwdata->desc.button_mask == 0) {
-            for (i = 0; i < hwdata->desc.nbuttons && i < sizeof(Uint16)*8; ++i) {
+            for (i = 0; i < hwdata->desc.nbuttons && i < sizeof(hwdata->desc.button_mask)*8; ++i) {
                 hwdata->desc.button_mask |= (1 << i);
             }
         }