Index: /trunk/src/VBox/VMM/VMMAll/IOMAllMMIO.cpp
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/IOMAllMMIO.cpp	(revision 52983)
+++ /trunk/src/VBox/VMM/VMMAll/IOMAllMMIO.cpp	(revision 52984)
@@ -94,5 +94,5 @@
 {
     AssertReturn(   (pRange->fFlags & IOMMMIO_FLAGS_WRITE_MODE) != IOMMMIO_FLAGS_WRITE_PASSTHRU
-                 || (pRange->fFlags & IOMMMIO_FLAGS_WRITE_MODE) <= IOMMMIO_FLAGS_WRITE_DWORD_QWORD_READ_MISSING,
+                 && (pRange->fFlags & IOMMMIO_FLAGS_WRITE_MODE) <= IOMMMIO_FLAGS_WRITE_DWORD_QWORD_READ_MISSING,
                  VERR_IOM_MMIO_IPE_1);
     AssertReturn(cbValue != 0 && cbValue <= 16, VERR_IOM_MMIO_IPE_2);