diff --git a/support/testing/tests/fs/test_ubi.py b/support/testing/tests/fs/test_ubi.py
index 7321f83da9..8148e5f336 100644
--- a/support/testing/tests/fs/test_ubi.py
+++ b/support/testing/tests/fs/test_ubi.py
@@ -25,7 +25,7 @@ class TestUbi(infra.basetest.BRTest):
         out = out.splitlines()
         self.assertIn("UBI image, version 1", out[0])
 
-        subprocess.call(["truncate", "-s 128M", img])
+        subprocess.call(["truncate", "-s 64M", img])
 
         self.emulator.boot(arch="armv7",
                            kernel="builtin",