diff --git a/petsc.spec b/petsc.spec
index 07f135a..54612ed 100644
--- a/petsc.spec
+++ b/petsc.spec
@@ -156,7 +156,8 @@ BuildRequires: MUMPS-devel
 BuildRequires: suitesparse-devel
 %endif
 %if %{with blas}
-%ifnarch x86_64 %{ix86} armv7hl %{power64} aarch64
+%{!?openblas_arches:%global openblas_arches x86_64 %{ix86} armv7hl %{power64} aarch64}
+%ifnarch %{openblas_arches}
 BuildRequires: blas-devel
 BuildRequires: lapack-devel
 %else