diff --git a/import-layers/yocto-poky/scripts/lib/wic/plugins/source/bootimg-efi.py b/import-layers/yocto-poky/scripts/lib/wic/plugins/source/bootimg-efi.py
index 8bc3622..4adb80b 100644
--- a/import-layers/yocto-poky/scripts/lib/wic/plugins/source/bootimg-efi.py
+++ b/import-layers/yocto-poky/scripts/lib/wic/plugins/source/bootimg-efi.py
@@ -234,5 +234,5 @@
         out = exec_cmd(du_cmd)
         bootimg_size = out.split()[0]
 
-        part.size = bootimg_size
+        part.size = int(bootimg_size)
         part.source_file = bootimg