diff --git a/README.md b/README.md
index b62f3b3..454419b 100644
--- a/README.md
+++ b/README.md
@@ -78,9 +78,15 @@ are some non-default options:
   application (kernel). However it prevents crashes because of NULL pointer
   dereference in other cases.
 * `--with-arch` - includes architecture-specific code (except assembly). May be
-  useful for testing.
+  useful for testing. You can also separately enable or disable components:
+  * `--with-arch-i386`
+  * `--with-arch-x86-64`
 * `--with-libc` - provides the replacement for some standard C functions. Useful
-  in freestanding environment, where no libc is present.
+  in freestanding environment, where no libc is present. You can also separately
+  enable or disable components:
+  * `--with-libc-memset`
+  * `--with-libc-strcpy`
+  * `--with-libc-strlen`
 
 ### Installation