diff --git a/conf/modules/gps_piksi.xml b/conf/modules/gps_piksi.xml
index 0e9ee3c6b8..ae2fc05845 100644
--- a/conf/modules/gps_piksi.xml
+++ b/conf/modules/gps_piksi.xml
@@ -23,9 +23,9 @@
     <configure name="PIKSI_GPS_BAUD" default="B115200"/>
 
     <file name="gps_piksi.c" dir="subsystems/gps"/>
-    <include name="$(PAPARAZZI_SRC)/sw/ext/libsbp/c/include"/>
-    <file name="sbp.c" dir="$(PAPARAZZI_SRC)/sw/ext/libsbp/c/src"/>
-    <file name="edc.c" dir="$(PAPARAZZI_SRC)/sw/ext/libsbp/c/src"/>
+    <include name="../ext/libsbp/c/include"/>
+    <file name="sbp.c" dir="../ext/libsbp/c/src"/>
+    <file name="edc.c" dir="../ext/libsbp/c/src"/>
 
     <define name="USE_$(PIKSI_GPS_PORT_UPPER)"/>
     <define name="PIKSI_GPS_LINK" value="$(PIKSI_GPS_PORT_LOWER)"/>
diff --git a/sw/tools/find_vpaths.py b/sw/tools/find_vpaths.py
index 17adade36b..1b56305350 100755
--- a/sw/tools/find_vpaths.py
+++ b/sw/tools/find_vpaths.py
@@ -56,14 +56,17 @@ with open(sys.argv[2]) as fp:
         found = 0
         for vpath in vpaths:
             if os.path.isfile(path.join(vpath, f)) :
-                cmd = cmd + path.join(vpath, f) + ' '
-                found = found +1
+                if found == 0:
+                    # add file in the path only once
+                    cmd = cmd + path.join(vpath, f) + ' '
+                    found = found +1
                 # break
         if found == 0:
             tmps = "ERROR: could not find src: " + f
             cmd = cmd + tmps #hack to make the error known
             print(tmps)            
         if found > 1:
+            # NOTE: this will never happen
             tmps = "ERROR: found src more than once: " + f
             cmd = cmd + tmps #hack to make the error known
             print(tmps)