diff -ur a/conftest.sh b/conftest.sh
--- a/conftest.sh	2011-06-10 22:04:05.411192053 +0200
+++ b/conftest.sh	2011-06-02 21:51:49.000000000 +0200
@@ -76,7 +76,7 @@
 }
 
 build_cflags() {
-    BASE_CFLAGS="-D__KERNEL__ \
+    BASE_CFLAGS="-O2 -D__KERNEL__ \
 -DKBUILD_BASENAME=\"#conftest$$\" -DKBUILD_MODNAME=\"#conftest$$\" \
 -nostdinc -isystem $ISYSTEM"
 
diff -ur a/nv-linux.h b/nv-linux.h
--- a/nv-linux.h	2011-06-10 22:02:01.091192102 +0200
+++ b/nv-linux.h	2011-06-10 21:47:02.901192468 +0200
@@ -44,7 +44,7 @@
 #  define KERNEL_2_4
 #elif LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 0)
 #  error This driver does not support 2.5 kernels!
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(2, 7, 0)
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(4, 0, 0)
 #  define KERNEL_2_6
 #else
 #  error This driver does not support development kernels!