diff --git a/src/via_ums.c b/src/via_ums.c
index e8542d6..9c203f2 100644
--- a/src/via_ums.c
+++ b/src/via_ums.c
@@ -867,12 +867,13 @@ umsPreInit(ScrnInfoPtr pScrn)
                           pVia->PciInfo->func);
 #endif
 
+    if (!viaMapFB(pScrn))
+        return FALSE;
+
     /* Detect the amount of installed RAM */
     if (!viaMapMMIO(pScrn))
         return FALSE;
 
-    if (!viaMapFB(pScrn))
-        return FALSE;
     return TRUE;
 }