Index: uspace/srv/bd/part/guid_part/guid_part.c
===================================================================
--- uspace/srv/bd/part/guid_part/guid_part.c	(revision 991f645937e5e281d6996ad4623f9ab33c71916d)
+++ uspace/srv/bd/part/guid_part/guid_part.c	(revision 7e752b2a0d66c871748e5fa9e8bbe3a27c70a202)
@@ -155,5 +155,5 @@
 
 	if (block_size < 512 || (block_size % 512) != 0) {
-		printf(NAME ": invalid block size %d.\n");
+		printf(NAME ": invalid block size %zu.\n", block_size);
 		return ENOTSUP;
 	}
Index: uspace/srv/bd/part/mbr_part/mbr_part.c
===================================================================
--- uspace/srv/bd/part/mbr_part/mbr_part.c	(revision 991f645937e5e281d6996ad4623f9ab33c71916d)
+++ uspace/srv/bd/part/mbr_part/mbr_part.c	(revision 7e752b2a0d66c871748e5fa9e8bbe3a27c70a202)
@@ -206,5 +206,5 @@
 
 	if (block_size < 512 || (block_size % 512) != 0) {
-		printf(NAME ": invalid block size %d.\n");
+		printf(NAME ": invalid block size %zu.\n", block_size);
 		return ENOTSUP;
 	}