diff --git a/sys/bootstrap/tar.c b/sys/bootstrap/tar.c
index 966b03a..7be6544 100644
--- a/sys/bootstrap/tar.c
+++ b/sys/bootstrap/tar.c
@@ -74,8 +74,10 @@ int tar_open(struct tar *tar, const char *path, struct tar_file *out)
 		}
 
 		s += header.size;
-		s += ((sizeof *bin_header)
-		      - ((uintptr_t)s % (sizeof *bin_header)));
+		if ((uintptr_t)s % (sizeof *bin_header)) {
+			s += ((sizeof *bin_header)
+			      - ((uintptr_t)s % (sizeof *bin_header)));
+		}
 
 		bin_header = (struct tar_bin_header *)s;
 	}
@@ -382,8 +384,10 @@ static enum fs_status build_dentry_tree(
 		}
 
 		s += header.size;
-		s += ((sizeof *bin_header)
-		      - ((uintptr_t)s % (sizeof *bin_header)));
+		if ((uintptr_t)s % (sizeof *bin_header)) {
+			s += ((sizeof *bin_header)
+			      - ((uintptr_t)s % (sizeof *bin_header)));
+		}
 
 		bin_header = (struct tar_bin_header *)s;
 	}