diff --git a/arch/sim/src/sim/up_x11framebuffer.c b/arch/sim/src/sim/up_x11framebuffer.c
index 94cd92248fb..7065a9448b3 100644
--- a/arch/sim/src/sim/up_x11framebuffer.c
+++ b/arch/sim/src/sim/up_x11framebuffer.c
@@ -317,8 +317,8 @@ static inline int up_x11mapsharedmem(int depth, unsigned int fblen)
           goto shmerror;
         }
 
+      g_framebuffer = (unsigned char *)g_image->data;
       g_shmcheckpoint++;
-
     }
   else
 #endif