diff --git a/setup/srcconf.c b/setup/srcconf.c
index 967aed3..0300496 100644
--- a/setup/srcconf.c
+++ b/setup/srcconf.c
@@ -952,7 +952,7 @@ printf("Symlink %s -> %s\n", source, target);
 #if defined(__SCO_VERSION__)
       fprintf (f, "CFLAGS=-O -D_KERNEL -D_DDI=8\n");
 #else
-      fprintf (f, "CFLAGS += -D_KERNEL\n");
+      fprintf (f, "CFLAGS += -no-pie -D_KERNEL\n");
 #endif
 #ifdef HAVE_KERNEL_FLAGS
       add_kernel_flags (f);
diff --git a/setup/srcconf_linux.inc b/setup/srcconf_linux.inc
index dfae1fc..3741014 100644
--- a/setup/srcconf_linux.inc
+++ b/setup/srcconf_linux.inc
@@ -51,7 +51,7 @@ add_kernel_flags (FILE * f)
 {
 # if defined(__x86_64__)
   fprintf (f,
-        "CFLAGS += -O3 -fno-common -mcmodel=kernel  -mno-red-zone -fno-pie  -fno-asynchronous-unwind-tables -ffreestanding%s\n", fnsp);
+        "CFLAGS += -O2 -fno-common -mcmodel=kernel  -mno-red-zone -fno-pie  -fno-asynchronous-unwind-tables -ffreestanding%s\n", fnsp);
 # else
 #   ifndef __arm__
   if (getenv ("NO_REGPARM") == NULL)