diff --git a/src/wic/plugins/source/bootimg_efi.py b/src/wic/plugins/source/bootimg_efi.py
index fe6c222..7cdd444 100644
--- a/src/wic/plugins/source/bootimg_efi.py
+++ b/src/wic/plugins/source/bootimg_efi.py
@@ -171,7 +171,7 @@ class BootimgEFIPlugin(SourcePlugin):
                              "%s for systemd-boots's boot.conf", configfile)
             else:
                 raise WicError("configfile is specified but failed to "
-                               "get it from %s.", configfile)
+                               "get it from %s." % configfile)
         else:
             # Create systemd-boot configuration using parameters from wks file
             kernel = get_bitbake_var("KERNEL_IMAGETYPE")
diff --git a/src/wic/plugins/source/isoimage_isohybrid.py b/src/wic/plugins/source/isoimage_isohybrid.py
index 0a3ecd3..15dae01 100644
--- a/src/wic/plugins/source/isoimage_isohybrid.py
+++ b/src/wic/plugins/source/isoimage_isohybrid.py
@@ -101,7 +101,7 @@ class IsoImagePlugin(SourcePlugin):
                              configfile)
             else:
                 raise WicError("configfile is specified "
-                               "but failed to get it from %s", configfile)
+                               "but failed to get it from %s" % configfile)
         else:
             splash = os.path.join(target_dir, "splash.jpg")
             if os.path.exists(splash):