diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5863e343..6bfc6514 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -37,7 +37,7 @@ jobs:
       - run: opam exec -- dune build @install
 
       # install some depopts
-      - run: opam install thread-local-storage trace domain-local-await
+      - run: opam pin picos --dev -y -n && opam install thread-local-storage trace domain-local-await # picos
         if: matrix.ocaml-compiler == '5.2'
 
       - run: opam exec -- dune build --profile=release --force @install @runtest