diff --git a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c b/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c
index 1afd60ce66..7f4743b003 100644
--- a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c
+++ b/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c
@@ -581,7 +581,7 @@ NorFlashWriteSingleBlock (
     // contents, while checking whether the old version had any bits cleared
     // that we want to set. In that case, we will need to erase the block first.
     for (CurOffset = 0; CurOffset < *NumBytes; CurOffset++) {
-      if (~OrigData[CurOffset] & Buffer[CurOffset]) {
+      if (~(UINT32)OrigData[CurOffset] & (UINT32)Buffer[CurOffset]) {
         goto DoErase;
       }
 
diff --git a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.h b/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.h
index b7f5d208b2..455eafacc2 100644
--- a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.h
+++ b/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.h
@@ -61,7 +61,7 @@
 #define P30_MAX_BUFFER_SIZE_IN_BYTES  ((UINTN)128)
 #define P30_MAX_BUFFER_SIZE_IN_WORDS  (P30_MAX_BUFFER_SIZE_IN_BYTES/((UINTN)4))
 #define MAX_BUFFERED_PROG_ITERATIONS  10000000
-#define BOUNDARY_OF_32_WORDS          0x7F
+#define BOUNDARY_OF_32_WORDS          ((UINTN)0x7F)
 
 // CFI Addresses
 #define P30_CFI_ADDR_QUERY_UNIQUE_QRY  0x10