diff --git a/brial.changes b/brial.changes
index d8ce322..2130468 100644
--- a/brial.changes
+++ b/brial.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Tue Sep 22 22:07:50 UTC 2020 - Jan Engelhardt <jengelh@inai.de>
+
+- Update ax_boost_base.m4 during build with riscv64 support.
+
 -------------------------------------------------------------------
 Tue Sep  8 13:00:37 UTC 2020 - Jan Engelhardt <jengelh@inai.de>
 
diff --git a/brial.spec b/brial.spec
index a6d9669..7cfd1ff 100644
--- a/brial.spec
+++ b/brial.spec
@@ -25,6 +25,7 @@ License:        GPL-2.0-or-later
 Group:          Productivity/Scientific/Math
 URL:            https://github.com/BRiAl/BRiAl
 Source:         https://github.com/BRiAl/BRiAl/releases/download/%version/%name-%version.tar.bz2
+BuildRequires:  autoconf-archive
 BuildRequires:  automake
 BuildRequires:  gcc-c++
 BuildRequires:  libboost_headers-devel >= 1.58
@@ -74,7 +75,10 @@ developing with polybori/brial libraries.
 %autosetup -p1
 
 %build
+# refresh with riscv64 support
+rm -f m4/ax_boost_base.m4
 autoreconf -fi
+
 %configure --disable-static
 %make_build