add debug support to uuu in flash script.

scripts/librem5-devkit-flash-image

@@ -219,8 +219,11 @@ def write_uuu_script(target, image, uboot):
                                        uboot=os.path.basename(uboot)))
 
 
-def flash_image(uuu_target):
-    subprocess.check_call(['uuu', uuu_target])
+def flash_image(uuu_target, debug):
+    if debug:
+        subprocess.check_call(['uuu', '-v', uuu_target])
+    else:
+        subprocess.check_call(['uuu', uuu_target])
 
 
 def main():
@@ -283,7 +286,7 @@ def main():
         download_uboot(urljoin(uboot_ref['url'], 'artifact/build/{}'.format(UBOOT)),
                        uboot_target)
         write_uuu_script(uuu_target, image_target, uboot_target)
-        flash_image(uuu_target)
+        flash_image(uuu_target, args.debug)
     except VerifyImageException as e:
         logging.error(e)
         return 1