diff --git a/include/spi_flash.h b/include/spi_flash.h
index 7bb9aa70..9a635c1a 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -36,6 +36,8 @@
 #include <stdint.h>
 
 uint16_t spi_flash_probe(void);
+void spi_release(void);
+
 void spi_flash_sector_erase(uint32_t address);
 int spi_flash_read(uint32_t address, void *data, int len);
 int spi_flash_write(uint32_t address, const void *data, int len);
@@ -43,6 +45,7 @@ int spi_flash_write(uint32_t address, const void *data, int len);
 #else
 
 #define spi_flash_probe() do{}while(0)
+#define spi_release() do{}while(0)
 
 #endif /* SPI_FLASH */
 
diff --git a/src/image.c b/src/image.c
index cc56bfc4..878dee71 100644
--- a/src/image.c
+++ b/src/image.c
@@ -120,7 +120,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
 }
 #endif /* WOLFBOOT_SIGN_RSA2048 */
 
-static uint8_t get_header_ext(struct wolfBoot_image *img, uint16_t type, uint8_t **ptr);
+static uint16_t get_header_ext(struct wolfBoot_image *img, uint16_t type, uint8_t **ptr);
 
 static uint16_t get_header(struct wolfBoot_image *img, uint16_t type, uint8_t **ptr)
 {
diff --git a/src/spi_flash.c b/src/spi_flash.c
index eb534d71..4ba447fa 100644
--- a/src/spi_flash.c
+++ b/src/spi_flash.c
@@ -133,7 +133,7 @@ static int spi_flash_write_page(uint32_t address, const void *data, int len)
 static int spi_flash_write_sb(uint32_t address, const void *data, int len)
 {
     const uint8_t *buf = data;
-    const uint8_t verify;
+    uint8_t verify = 0;
     int j = 0;
     wait_busy();
     if (len < 1)
diff --git a/test-app/app_stm32f4.c b/test-app/app_stm32f4.c
index 248b997d..8370c503 100644
--- a/test-app/app_stm32f4.c
+++ b/test-app/app_stm32f4.c
@@ -33,13 +33,6 @@
 
 #ifdef PLATFORM_stm32f4
 
-#ifdef SPI_FLASH
-extern void spi_release(void);
-#else
-#define spi_release() do{}while(0)
-#endif
-
-
 #define UART1 (0x40011000)
 
 #define UART1_SR       (*(volatile uint32_t *)(UART1))