diff --git a/config/multithread b/config/multithread
index 6d052382a9..34ccc0b1f7 100644
--- a/config/multithread
+++ b/config/multithread
@@ -147,7 +147,8 @@ start_multithread_build() {
   echo 0 >"${THREAD_CONTROL}/status.max"
   touch "${THREAD_CONTROL}/status"
 
-  [ "${THREADCOUNT}" = "0" ] && THREADCOUNT=1
+  # Increase file descriptors if building one thread/package
+  [ "${THREADCOUNT}" = "0" ] && ulimit -n ${ULIMITN:-10240}
 
   # Bootstrap GNU parallel
   MTWITHLOCKS=no $SCRIPTS/build parallel:host 2>&1 || die "Unable to bootstrap parallel package"