diff --git a/pkgs/development/libraries/xsimd/default.nix b/pkgs/development/libraries/xsimd/default.nix
index 3a9a90fbe2bc82e..2a72626bdd33765 100644
--- a/pkgs/development/libraries/xsimd/default.nix
+++ b/pkgs/development/libraries/xsimd/default.nix
@@ -56,5 +56,6 @@ stdenv.mkDerivation (finalAttrs: {
     license = licenses.bsd3;
     maintainers = with maintainers; [ tobim ];
     platforms = platforms.all;
+    badPlatforms = [ lib.systems.inspect.patterns.isPower ];  # no AltiVec support, build fails
   };
 })
diff --git a/pkgs/development/python-modules/pythran/default.nix b/pkgs/development/python-modules/pythran/default.nix
index 2c4095b532f5bb2..964582d4af062fb 100644
--- a/pkgs/development/python-modules/pythran/default.nix
+++ b/pkgs/development/python-modules/pythran/default.nix
@@ -36,7 +36,7 @@ in buildPythonPackage rec {
   ];
 
   # xsimd: unvendor this header-only C++ lib
-  postPatch = ''
+  postPatch = lib.optionalString (lib.meta.availableOn stdenv.hostPlatform xsimd) ''
     rm -r third_party/xsimd
     ln -s '${lib.getDev xsimd}'/include/xsimd third_party/
   '';
diff --git a/pkgs/development/python-modules/scipy/default.nix b/pkgs/development/python-modules/scipy/default.nix
index 2c5ecd42585c540..3a4499dd4905c4d 100644
--- a/pkgs/development/python-modules/scipy/default.nix
+++ b/pkgs/development/python-modules/scipy/default.nix
@@ -99,6 +99,7 @@ in buildPythonPackage {
     lapack
     pybind11
     pooch
+  ] ++ lib.optionals (lib.meta.availableOn stdenv.hostPlatform xsimd) [
     xsimd
   ] ++ lib.optionals (pythonOlder "3.9") [
     libxcrypt