diff --git a/hw/application_fpga/fw/testfw/main.c b/hw/application_fpga/fw/testfw/main.c
index 81e6fbb..48d130a 100644
--- a/hw/application_fpga/fw/testfw/main.c
+++ b/hw/application_fpga/fw/testfw/main.c
@@ -187,6 +187,13 @@ int main()
 		anyfailed = 1;
 	}
 
+	// Should NOT be able to read from UDI in app-mode.
+	wordcpy(udi_local, (void *)udi, UDI_WORDS);
+	if (!memeq(udi_local, zeros, UDI_WORDS * 4)) {
+		puts("FAIL: Read from UDI in app-mode\r\n");
+		anyfailed = 1;
+	}
+
 	uint32_t cdi_local[CDI_WORDS];
 	uint32_t cdi_local2[CDI_WORDS];
 	wordcpy(cdi_local, (void *)cdi, CDI_WORDS);