diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/QemuFlash.c b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/QemuFlash.c
index 0d29bf701a..d19997032e 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/QemuFlash.c
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/QemuFlash.c
@@ -232,8 +232,8 @@ QemuFlashEraseBlock (
   }
 
   Ptr = QemuFlashPtr (Lba, 0);
-  *Ptr = BLOCK_ERASE_CMD;
-  *Ptr = BLOCK_ERASE_CONFIRM_CMD;
+  QemuFlashPtrWrite (Ptr, BLOCK_ERASE_CMD);
+  QemuFlashPtrWrite (Ptr, BLOCK_ERASE_CONFIRM_CMD);
   return EFI_SUCCESS;
 }