diff --git a/eic-spack.sh b/eic-spack.sh
index f876ebc82490fc7a4020770549d36283343d5d0e..d0f164b3c010ce1123afd121228f7c631538f454 100644
--- a/eic-spack.sh
+++ b/eic-spack.sh
@@ -3,7 +3,7 @@ EICSPACK_ORGREPO="eic/eic-spack"
 
 ## EIC spack github version, e.g. v0.19.7 or commit hash
 ## note: nightly builds will use e.g. releases/v0.19
-EICSPACK_VERSION="v0.20.11"
+EICSPACK_VERSION="v0.20.12"
 
 ## Space-separated list of eic-spack cherry-picks
 read -r -d '' EICSPACK_CHERRYPICKS <<- \
diff --git a/spack-environment/packages.yaml b/spack-environment/packages.yaml
index 6aa44f0d0356168107a6d3146e9c0dc5d2e24e68..1f27c2353aa0720f50a7b1fbef29d8919758be69 100644
--- a/spack-environment/packages.yaml
+++ b/spack-environment/packages.yaml
@@ -113,7 +113,7 @@ packages:
     - -debuginfod
   geant4:
     require:
-    - '@11.1.1'
+    - '@11.1.1.east'
     - cxxstd=17 -vecgeom +threads -vtk
     - any_of: [+opengl +qt +x11, -opengl -qt -x11]
   graphviz: