diff --git a/README.md b/README.md
index 547e541..7dc7ae6 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ applications up to 64 KB with a 64 KB stack.
 * [Threat Model](doc/threat_model/threat_model.md)
 * [Framing Protocol](doc/framing_protocol/framing_protocol.md)
 * [Boards](hw/boards/README.md)
+* [Software](doc/system_description/software.md)
 * [Firmware](hw/application_fpga/fw/mta1_mkdf/README.md)
 * [Toolchain setup](doc/toolchain_setup.md)
 * [Quickstart](doc/quickstart.md) to program the Tillitis Key 1