diff --git a/tools/boot/universe.sh b/tools/boot/universe.sh
new file mode 100755
index 000000000000..ee779a38ae5b
--- /dev/null
+++ b/tools/boot/universe.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+# $FreeBSD$
+
+#
+# Full list of all arches, but we only build a subset. All different mips add any
+# value, and there's a few others we just don't support.
+#
+#	mips/mipsel mips/mips mips/mips64el mips/mips64 mips/mipsn32 \
+#	mips/mipselhf mips/mipshf mips/mips64elhf mips/mips64hf \
+#	powerpc/powerpc powerpc/powerpc64 powerpc/powerpcspe \
+#	riscv/riscv64 riscv/riscv64sf
+#
+# This script is expected to be run in sys/boot (though you could run it anywhere
+# in the tree). It does a full clean build. For sys/boot you can do all the archs in
+# about a minute or two on a fast machine. It's also possible that you need a full
+# make universe for this to work completely.
+#
+# Output is put into _.boot.$TARGET_ARCH.log in sys.boot.
+#
+
+for i in \
+	amd64/amd64 \
+	arm/arm arm/armeb arm/armv7 \
+	arm64/aarch64 \
+	i386/i386 \
+	mips/mips mips/mips64 \
+	powerpc/powerpc powerpc/powerpc64 \
+	sparc64/sparc64 \
+	; do
+    ta=${i##*/}
+    echo -n "Building $ta..."
+    ( ( make buildenv TARGET_ARCH=$ta BUILDENV_SHELL="make -j 20 clean cleandepend cleandir obj depend all" \
+	 > _.boot.${ta}.log 2>&1 ) && echo Success ) || echo Fail
+done
+
+
+