diff --git a/sys-cluster/mrnet/files/mrnet-no-libi.patch b/sys-cluster/mrnet/files/mrnet-no-libi.patch
new file mode 100644
index 0000000000..8864c520d4
--- /dev/null
+++ b/sys-cluster/mrnet/files/mrnet-no-libi.patch
@@ -0,0 +1,32 @@
+--- a/conf/Makefile.in
++++ b/conf/Makefile.in
+@@ -191,8 +191,8 @@
+ 
+ 
+ LIBI_TARGETS = 
+-LIBLIBI = $(LIBDIR)/liblibi.a
+-LIBLIBI_SO = $(LIBDIR)/liblibi.so
++LIBLIBI =
++LIBLIBI_SO =
+ ifeq ($(MRNET_STARTUP_METHOD),libi)
+     LIBI_TARGETS = $(LIBLIBI)
+     ifeq ($(BUILD_SHARED_LIBS), yes)
+@@ -388,9 +388,6 @@
+ 
+ INSTALL_PREREQ = install-prep 
+ INSTALL_PREREQ += xplat-install xplat_lightweight-install
+-ifeq ($(MRNET_STARTUP_METHOD),libi)
+-    INSTALL_PREREQ += libi-install
+-endif
+ INSTALL_PREREQ += install-local lightweight-install 
+ 
+ install: $(INSTALL_PREREQ)
+@@ -511,7 +508,7 @@
+ 
+ $(LIBXPLAT_LIGHTWEIGHT_SO): xplat_lightweight-sharedobj
+ 
+-$(LIBI_TARGETS): libi-all
++$(LIBI_TARGETS):
+ 
+ $(LIBLMON):
+ 
diff --git a/sys-cluster/mrnet/metadata.xml b/sys-cluster/mrnet/metadata.xml
index e2be8a6937..069e7794fd 100644
--- a/sys-cluster/mrnet/metadata.xml
+++ b/sys-cluster/mrnet/metadata.xml
@@ -45,9 +45,9 @@ multicast operations may be in progress simultaneously.
 * Open source licensing.
 	</longdescription>
 	<use>
-		<!--<flag name="libi">Use libi as tree instantiation method instead of ssh</flag>-->
+		<flag name="libi">Use libi as tree instantiation method instead of ssh</flag>
 		<flag name="threadsafe">Build threasafe version of lightweight MRNet and XPlat libraries</flag>
-		<!--<flag name="slurm">Use slurm as libi tree instantiation method instead of ssh</flag>-->
+		<flag name="slurm">Use slurm as libi tree instantiation method instead of ssh</flag>
 	</use>
 	<upstream>
 		<bugs-to>https://github.com/dyninst/mrnet/issues</bugs-to>
diff --git a/sys-cluster/mrnet/mrnet-5.0.1_p20180510-r2.ebuild b/sys-cluster/mrnet/mrnet-5.0.1_p20180510-r3.ebuild
similarity index 58%
rename from sys-cluster/mrnet/mrnet-5.0.1_p20180510-r2.ebuild
rename to sys-cluster/mrnet/mrnet-5.0.1_p20180510-r3.ebuild
index 74c5db51f1..2cbbb0a0bd 100644
--- a/sys-cluster/mrnet/mrnet-5.0.1_p20180510-r2.ebuild
+++ b/sys-cluster/mrnet/mrnet-5.0.1_p20180510-r3.ebuild
@@ -1,10 +1,12 @@
 # Copyright 2019-2021 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
-EAPI=8
+EAPI=7
 
 COMMIT="7375ba5bb0df87c68e58ad15e9e5e351ae020c08"
 
+inherit flag-o-matic
+
 DESCRIPTION="A Multicast/Reduction Network"
 HOMEPAGE="http://www.paradyn.org/mrnet"
 SRC_URI="https://github.com/dyninst/mrnet/archive/${COMMIT}.tar.gz -> ${P}.tar.gz"
@@ -13,15 +15,22 @@ S="${WORKDIR}/${PN}-${COMMIT}"
 LICENSE="LGPL-2.1+"
 SLOT="0"
 KEYWORDS="~amd64"
-IUSE="threadsafe" #launchmon libi slurm
+IUSE="libi slurm threadsafe"
 
-RDEPEND="dev-libs/boost:="
+RDEPEND="
+	dev-libs/boost:=
+	libi? (
+		sys-cluster/launchmon
+		sys-cluster/libi
+	)
+"
 DEPEND="
 	${RDEPEND}
+	slurm? ( sys-cluster/slurm )
 "
-#	slurm? ( sys-cluster/slurm )
 
-#REQUIRED_USE="slurm? ( libi )"
+PATCHES=( "${FILESDIR}/${PN}-no-libi.patch" )
+REQUIRED_USE="slurm? ( libi )"
 
 src_prepare() {
 	rm -r external || die
@@ -29,6 +38,7 @@ src_prepare() {
 }
 
 src_configure() {
+	use libi && append-cxxflags "-llibi"
 	local myconf=(
 		--enable-shared
 		--enable-verbosebuild
@@ -37,25 +47,16 @@ src_configure() {
 		$(use_enable threadsafe ltwt-threadsafe)
 	)
 
-#expat seems to be used only on cray
-#	if use expat; then
-#		myconf+=( "--with-expat=${EPREFIX}/usr" )
-#	else
-#		myconf+=( "--without-expat" )
-#	fi
-#	if use launchmon; then
-#		myconf+=( "--with-launchmon=${EPREFIX}/usr" )
-#	else
-#		myconf+=( "--without-launchmon" )
-#	fi
-#	if use libi; then
-#		myconf+=( "--with-libi=${EPREFIX}/usr" )
-#		myconf+=( "--with-startup=libi" )
-#		use slurm && myconf+=( "--with-libi-startup=slurm" )
-#	else
-#		myconf+=( "--without-libi" )
-#		myconf+=( "--with-startup=ssh" )
-#	fi
+	if use libi; then
+		myconf+=( "--with-launchmon=${EPREFIX}/usr" )
+		myconf+=( "--with-libi=${EPREFIX}/usr" )
+		myconf+=( "--with-startup=libi" )
+		use slurm && myconf+=( "--with-libi-startup=slurm" )
+	else
+		myconf+=( "--without-launchmon" )
+		myconf+=( "--without-libi" )
+		myconf+=( "--with-startup=ssh" )
+	fi
 
 	econf "${myconf[@]}"
 }