diff --git a/etc/README.md b/etc/README.md
index 31bbaff..e501b35 100644
--- a/etc/README.md
+++ b/etc/README.md
@@ -229,7 +229,7 @@ usage: ./build.sh [-a nt32|nt64] [-b debug|release] [-C dir[,..]] [-d] [-D kind[
                           new commits.
         --debug-minipix   Don't strip(1) minipix binaries to facilitate debugging minipix.
         --dump-on-abort   Produce package environment dump files on build failure to be
-                          used in conjuction with pkg_shell.sh script.
+                          used in conjuction with pkg_shell.sh script (excludes -R.)
         <group>[ ..]      One of: dev_packages, dist, host_deps, host_deps_rpm,
                           host_toolchain, host_tools, minipix, native_packages,
                           native_runtime, native_toolchain, native_tools.
diff --git a/etc/build.usage b/etc/build.usage
index d945317..f287b98 100644
--- a/etc/build.usage
+++ b/etc/build.usage
@@ -48,7 +48,7 @@ usage: ./build.sh [-a nt32|nt64] [-b debug|release] [-C dir[,..]] [-d] [-D kind[
                           new commits.
         --debug-minipix   Don't strip(1) minipix binaries to facilitate debugging minipix.
         --dump-on-abort   Produce package environment dump files on build failure to be
-                          used in conjuction with pkg_shell.sh script.
+                          used in conjuction with pkg_shell.sh script (excludes -R.)
         <group>[ ..]      One of: dev_packages, dist, host_deps, host_deps_rpm,
                           host_toolchain, host_tools, minipix, native_packages,
                           native_runtime, native_toolchain, native_tools.
diff --git a/subr/build_init.subr b/subr/build_init.subr
index e07faca..c5f9117 100644
--- a/subr/build_init.subr
+++ b/subr/build_init.subr
@@ -162,18 +162,22 @@ buildp_init_getopts() {
 		fi;
 	done;
 	if [ "${_rc}" -eq 0 ]; then
-		while [ ${#} -gt 0 ]; do
-		if [ "${1#\*}" != "${1}" ]; then
-			BUILD_GROUPS_INHIBIT_DEPS=1; _arg="${1#\*}";
-		else
-			_arg="${1}";
+		if [ "${ARG_DUMP_ON_ABORT:-0}" -eq 1 ]\
+		&& [ "${ARG_RELAXED:-0}" -eq 1 ]; then
+			_rc=1; _status="Error: --dump-on-abort excludes -R.";
+		else	while [ ${#} -gt 0 ]; do
+			if [ "${1#\*}" != "${1}" ]; then
+				BUILD_GROUPS_INHIBIT_DEPS=1; _arg="${1#\*}";
+			else
+				_arg="${1}";
+			fi;
+			case "${_arg}" in
+			*=*)		rtl_set_var_unsafe "${_arg%%=*}" "${_arg#*=}"; ;;
+			[^a-zA-Z]*)	_rc=1; _status="Error: build group names must start with [a-zA-Z] (in argument \`${_arg}'.)"; ;;
+			*[^_a-zA-Z]*)	_rc=1; _status="Error: build group names must not contain [^_a-zA-Z] (in argument \`${_arg}'.)"; ;;
+			*)		BUILD_GROUPS="$(rtl_lconcat "${BUILD_GROUPS}" "${_arg}")"; ;;
+			esac; shift; done;
 		fi;
-		case "${_arg}" in
-		*=*)		rtl_set_var_unsafe "${_arg%%=*}" "${_arg#*=}"; ;;
-		[^a-zA-Z]*)	_rc=1; _status="Error: build group names must start with [a-zA-Z] (in argument \`${_arg}'.)"; ;;
-		*[^_a-zA-Z]*)	_rc=1; _status="Error: build group names must not contain [^_a-zA-Z] (in argument \`${_arg}'.)"; ;;
-		*)		BUILD_GROUPS="$(rtl_lconcat "${BUILD_GROUPS}" "${_arg}")"; ;;
-		esac; shift; done;
 	fi;
 	return "${_rc}";
 };