diff --git a/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.c b/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.c
index 6223895620..a2583a490c 100644
--- a/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.c
+++ b/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.c
@@ -258,7 +258,7 @@ Mtftp4GetMapping (
     return FALSE;
   }
 
-  while (!EFI_ERROR (gBS->CheckEvent (Service->TimerToGetMap))) {
+  while (EFI_ERROR (gBS->CheckEvent (Service->TimerToGetMap))) {
     Udp->Poll (Udp);
 
     if (!EFI_ERROR (Udp->GetModeData (Udp, NULL, &Ip4Mode, NULL, NULL)) &&