Index: uspace/app/mkminix/mkminix.c
===================================================================
--- uspace/app/mkminix/mkminix.c	(revision c4c7f5adeee8ccadf8750e0d5713917a30d83a6e)
+++ uspace/app/mkminix/mkminix.c	(revision 7a34efde7ef1777cd6e6c71b7bac49b56d579040)
@@ -278,5 +278,5 @@
 	void *root_block;
 	int rc;
-	const long root_dblock = sb->first_data_zone * (sb->block_size / MFS_MIN_BLOCKSIZE);
+	const long root_dblock = CONVERT_1K_OFF(sb->first_data_zone, sb->block_size);
 
 	root_block = (void *) malloc(MFS_MIN_BLOCKSIZE);