diff --git a/packages/meta-brainscales/package.py b/packages/meta-brainscales/package.py
index 383159fe5c20cdfc8c067d71d4e2d65458d50a3d..a99210c9d1ffaa8d3dc3e61c48d1b43e75d25f5b 100644
--- a/packages/meta-brainscales/package.py
+++ b/packages/meta-brainscales/package.py
@@ -49,7 +49,7 @@ class MetaBrainscales(Package):
     depends_on('py-matplotlib')
     depends_on('py-nose')
     depends_on('py-numpy')
-    depends_on('py-pybind11')
+    depends_on('py-pybind11@2.6.0:2.6.999') # workaround concretization error (py-scipy doesn't like 2.7)
     depends_on('py-pybind11-stubgen')
     depends_on('py-pycodestyle')
     depends_on('py-pyelftools')