diff --git a/tests/pkg_c25519/tests/01-run.py b/tests/pkg_c25519/tests/01-run.py
index d90541ef39..f049f3179c 100755
--- a/tests/pkg_c25519/tests/01-run.py
+++ b/tests/pkg_c25519/tests/01-run.py
@@ -12,7 +12,10 @@ import sys
 
 
 def testfunc(child):
-    child.expect(r"OK \(2 tests\)")
+    board = os.environ['BOARD']
+    # Increase timeout on "real" hardware
+    timeout = 20 if board is not 'native' else -1
+    child.expect(r"OK \(2 tests\)", timeout=timeout)
 
 
 if __name__ == "__main__":