diff --git a/docs/build.md b/docs/build.md
index cc7a80d..947d929 100644
--- a/docs/build.md
+++ b/docs/build.md
@@ -178,4 +178,4 @@ The Makefile will build the firmware in a docker container and leave the binary
 
 ## APDU Specifications
 
-- [APDU Protocol](APDUSPEC.md)
+- [APDU Protocol](./APDUSPEC.md)