diff --git a/examples/slave/nuttx/xmc4800/boards/relax/defconfig b/examples/slave/nuttx/xmc4800/boards/relax/defconfig
index 3471346a..2304102e 100644
--- a/examples/slave/nuttx/xmc4800/boards/relax/defconfig
+++ b/examples/slave/nuttx/xmc4800/boards/relax/defconfig
@@ -27,6 +27,7 @@ CONFIG_HAVE_CXX=y
 CONFIG_INIT_STACKSIZE=30000
 CONFIG_INTELHEX_BINARY=y
 CONFIG_LIBCXXTOOLCHAIN=y
+CONFIG_LIBC_LOCALE=y
 CONFIG_LIBM=y
 CONFIG_PREALLOC_TIMERS=4
 CONFIG_PTHREAD_MUTEX_TYPES=y