diff --git a/flight/tests/logfs/Makefile b/flight/tests/logfs/Makefile
index a1c302a1c..dc939c067 100644
--- a/flight/tests/logfs/Makefile
+++ b/flight/tests/logfs/Makefile
@@ -34,6 +34,8 @@ CFLAGS += -Wall -Werror
 CFLAGS += -g
 CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS)) -I.
 
+CFLAGS += "-DFLASH_IMAGE_FILE=\"$(OUTDIR)/theflash.bin\""
+
 CONLYFLAGS += -std=gnu99
 
 SRC := $(PIOS)/Common/pios_flashfs_logfs.c
diff --git a/flight/tests/logfs/pios_flash_ut.c b/flight/tests/logfs/pios_flash_ut.c
index aa7728352..32a749783 100644
--- a/flight/tests/logfs/pios_flash_ut.c
+++ b/flight/tests/logfs/pios_flash_ut.c
@@ -41,7 +41,7 @@ int32_t PIOS_Flash_UT_Init(uintptr_t * flash_id, const struct pios_flash_ut_cfg
 	flash_dev->cfg = cfg;
 	flash_dev->transaction_in_progress = false;
 
-	flash_dev->flash_file = fopen ("theflash.bin", "rb+");
+	flash_dev->flash_file = fopen (FLASH_IMAGE_FILE, "rb+");
 	if (flash_dev->flash_file == NULL) {
 		return -1;
 	}
diff --git a/flight/tests/logfs/pios_flash_ut_priv.h b/flight/tests/logfs/pios_flash_ut_priv.h
index a38bf21e2..90a4aeba9 100644
--- a/flight/tests/logfs/pios_flash_ut_priv.h
+++ b/flight/tests/logfs/pios_flash_ut_priv.h
@@ -8,3 +8,7 @@ struct pios_flash_ut_cfg {
 int32_t PIOS_Flash_UT_Init(uintptr_t * flash_id, const struct pios_flash_ut_cfg * cfg);
 
 extern const struct pios_flash_driver pios_ut_flash_driver;
+
+#if !defined(FLASH_IMAGE_FILE)
+#define FLASH_IMAGE_FILE "theflash.bin"
+#endif
diff --git a/flight/tests/logfs/unittest.cpp b/flight/tests/logfs/unittest.cpp
index c7e04f555..c0c383e76 100644
--- a/flight/tests/logfs/unittest.cpp
+++ b/flight/tests/logfs/unittest.cpp
@@ -35,7 +35,7 @@ class LogfsTestRaw : public testing::Test {
 protected:
   virtual void SetUp() {
     /* create an empty, appropriately sized flash filesystem */
-    FILE * theflash = fopen("theflash.bin", "wb");
+    FILE * theflash = fopen(FLASH_IMAGE_FILE, "wb");
     uint8_t sector[flash_config.size_of_sector];
     memset(sector, 0xFF, sizeof(sector));
     for (uint32_t i = 0; i < flash_config.size_of_flash / flash_config.size_of_sector; i++) {