diff --git a/Makefile b/Makefile
index d5618df..fd4db18 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@ install.radare.projects:
 
 #
 # If we have an extractor for this image, use it
-%.img:  %.extract %.img.sum
+%.img:  %.extract %.img.sha1
 	./$< > $@
-	sha1sum -c $@.sum
+	sha1sum -c $@.sha1
 
diff --git a/x220.8DHT34WW.img.sum b/x220.8DHT34WW.img.sha1
similarity index 100%
rename from x220.8DHT34WW.img.sum
rename to x220.8DHT34WW.img.sha1