diff --git a/support/testing/tests/fs/test_ubi.py b/support/testing/tests/fs/test_ubi.py
index 8148e5f336..eeb55b1d59 100644
--- a/support/testing/tests/fs/test_ubi.py
+++ b/support/testing/tests/fs/test_ubi.py
@@ -32,7 +32,7 @@ class TestUbi(infra.basetest.BRTest):
                            kernel_cmdline=["root=ubi0:rootfs",
                                            "ubi.mtd=0",
                                            "rootfstype=ubifs"],
-                           options=["-drive", "file={},if=pflash".format(img)])
+                           options=["-drive", "file={},if=pflash,format=raw".format(img)])
         self.emulator.login()
         cmd = "mount | grep 'ubi0:rootfs on / type ubifs'"
         _, exit_code = self.emulator.run(cmd)