diff --git a/openmeeg-fix_libmatio1518_compatibility.patch b/openmeeg-fix_libmatio1518_compatibility.patch
new file mode 100644
index 0000000..a655972
--- /dev/null
+++ b/openmeeg-fix_libmatio1518_compatibility.patch
@@ -0,0 +1,39 @@
+From d1ea0263b95c099e348b75171871d35172855649 Mon Sep 17 00:00:00 2001
+From: Theodore Papadopoulo <Theodore.Papadopoulo@inria.fr>
+Date: Mon, 28 Sep 2020 11:11:18 +0200
+Subject: [PATCH] Adapt MatlabIO.H to handle both older and newer version of
+ matio (up to matio 1.5.18).
+
+---
+ OpenMEEGMaths/include/MatlabIO.H | 17 ++++++++++++-----
+ 1 file changed, 12 insertions(+), 5 deletions(-)
+
+diff --git a/OpenMEEGMaths/include/MatlabIO.H b/OpenMEEGMaths/include/MatlabIO.H
+index 554df3d8..e4f4401c 100644
+--- a/OpenMEEGMaths/include/MatlabIO.H
++++ b/OpenMEEGMaths/include/MatlabIO.H
+@@ -352,12 +352,19 @@ namespace OpenMEEG {
+                     tank_inverted[std::pair<size_t,size_t>(j,i)] = val;
+                 }
+ 
+-                const int sz = linop.size();
+-                const int num = linop.ncol()+1;
+ 
+-                double* t  = new double[sz];
+-                int*    ir = new int[sz];
+-                int*    jc = new int[num];
++                #if MATIO_VERSION>=1518
++                    typedef mat_uint32_t matio_int_type;
++                #else
++                    typedef int matio_int_type;
++                #endif
++
++                const matio_int_type sz  = linop.size();
++                const matio_int_type num = linop.ncol()+1;
++                matio_int_type*      ir  = new matio_int_type[sz];
++                matio_int_type*      jc  = new matio_int_type[num];
++
++                double* t = new double[sz];
+ 
+                 size_t cnt = 0;
+                 size_t current_col = (size_t)-1;
diff --git a/openmeeg.spec b/openmeeg.spec
index 040006d..6411ed4 100644
--- a/openmeeg.spec
+++ b/openmeeg.spec
@@ -40,6 +40,9 @@ Patch1: %{name}-flexiblas_libraries.patch
 Patch2: %{name}-python_install_destination.patch
 Patch3: %{name}-bug385.patch
 
+# https://github.com/openmeeg/openmeeg/issues/421
+Patch4: %{name}-fix_libmatio1518_compatibility.patch
+
 BuildRequires: cmake3
 BuildRequires: gcc-c++, git, chrpath
 BuildRequires: gnuplot, wget, graphviz
@@ -189,8 +192,6 @@ ctest3 --force-new-ctest-process --parallel %{?_smp_mflags} -E 'openmeeg_python_
 %endif
 %endif
 
-%ldconfig_scriptlets
-
 %files
 %license LICENSE.txt
 %{_bindir}/*
@@ -219,8 +220,8 @@ ctest3 --force-new-ctest-process --parallel %{?_smp_mflags} -E 'openmeeg_python_
 %endif
 
 %changelog
-* Sun Sep 20 2020 Antonio Trande <sagitter@fedoraproject.org> - 2.4.2-0.9
-- Rebuild for matio-1.5.18
+* Mon Sep 28 2020 Antonio Trande <sagitter@fedoraproject.org> - 2.4.2-0.9
+- Rebuilt and patched for matio-1.5.18 (rhbz#1880819)
 
 * Fri Aug 14 2020 Iñaki Úcar <iucar@fedoraproject.org> - 2.4.2-0.8
 - https://fedoraproject.org/wiki/Changes/FlexiBLAS_as_BLAS/LAPACK_manager