diff --git a/utils/CMakeLists.txt b/utils/CMakeLists.txt
index 022b4c2455..74e7b28406 100644
--- a/utils/CMakeLists.txt
+++ b/utils/CMakeLists.txt
@@ -67,6 +67,7 @@ if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
     find_package(PkgConfig)
     pkg_check_modules(libusb QUIET REQUIRED IMPORTED_TARGET libusb-1.0)
     message("-- Found libusb: ${libusb_LINK_LIBRARIES}")
+    add_compile_definitions(USE_LIBUSBAPI)
 
     # optional system libs.
     pkg_check_modules(speex QUIET IMPORTED_TARGET speex speexdsp)
diff --git a/utils/mks5lboot/ipoddfu.c b/utils/mks5lboot/ipoddfu.c
index e5c811ee0a..e64599aa8c 100644
--- a/utils/mks5lboot/ipoddfu.c
+++ b/utils/mks5lboot/ipoddfu.c
@@ -245,6 +245,7 @@ struct dfuAPI {
 /*
  * DFU API low-level (specific) functions
  */
+#if defined(WIN32) || defined(USE_LIBUSBAPI) || defined(__APPLE__)
 static bool dfu_check_id(int vid, int pid, int *pid_list)
 {
     int *p;
@@ -263,6 +264,7 @@ static void dfu_add_reqerrstr(struct dfuDev *dfuh, struct usbControlSetup *cs)
         sizeof(dfuh->err) - strlen(dfuh->err), " (cs=%02x/%d/%d/%d/%d)",
         cs->bmRequestType, cs->bRequest, cs->wValue, cs->wIndex, cs->wLength);
 }
+#endif
 
 #ifdef WIN32
 static bool dfu_winapi_chkrc(struct dfuDev *dfuh, char *str, bool success)
@@ -695,7 +697,7 @@ static struct dfuAPI api_list[] =
  */
 static int DEBUG_DFUREQ = 0;
 
-static dfuAPIResult dfuapi_request(struct dfuDev *dfuh,
+static __attribute__ ((noinline)) dfuAPIResult dfuapi_request(struct dfuDev *dfuh,
                             struct usbControlSetup *cs, void *data)
 {
     if (!DEBUG_DFUREQ)
@@ -902,7 +904,7 @@ static int ipoddfu_download_file(struct dfuDev* dfuh,
 {
     unsigned int blknum, len, remaining;
     int poll_tmo;
-    DFUStatus status;
+    DFUStatus status = errNONE;
     DFUState state;
 
     if (dfuapi_req_getstate(dfuh, &state) != DFUAPISuccess)
diff --git a/utils/mks5lboot/mkdfu.c b/utils/mks5lboot/mkdfu.c
index 15b72303b1..ff9ca7041c 100644
--- a/utils/mks5lboot/mkdfu.c
+++ b/utils/mks5lboot/mkdfu.c
@@ -191,9 +191,9 @@ unsigned char *mkdfu(int dfu_type, char *dfu_arg, int* dfu_size,
 {
     const struct ipod_models *model = NULL;
     unsigned char *dfu_buf = NULL;
-    unsigned char *f_buf;
+    unsigned char *f_buf = NULL;
     int f_size;
-    uint32_t padded_bl_size;
+    uint32_t padded_bl_size = 0;
     uint32_t cert_off, cert_sz;
     off_t cur_off;
     char *dfu_desc;