diff --git a/README.md b/README.md
index 8d96bcf..a98136e 100644
--- a/README.md
+++ b/README.md
@@ -265,11 +265,13 @@ cope here.
 `m4` is the first piece of software we need in the autotools suite. It allows
 macros to be defined and files to be generated from those macros.
 
-#### Part 20: flex 2.5.11
+#### Part 22: flex 2.5.11
 `flex` is a tool for generating lexers or scanners: programs that recognize lexical patters.
 
 Unfortunately `flex` also depends on itself for compiling its own scanner, so
 first flex 2.5.11 is compiled, with its scanner definition manually modified so that
 it can be processed by lex for the Heirloom project (the required modifications
 are mostly syntactical, plus a few workarounds to avoid some flex advanced features).
-Then we recompile `flex` using its own lexer.
+
+### Part 23 flex 2.5.14
+Then we recompile unpatched `flex` using its own lexer.
diff --git a/rootfs.sh b/rootfs.sh
index 5ebda98..89f2d02 100755
--- a/rootfs.sh
+++ b/rootfs.sh
@@ -132,6 +132,9 @@ get_file https://ftp.gnu.org/gnu/m4/m4-1.4.tar.gz
 # flex 2.5.11
 get_file http://download.nust.na/pub2/openpkg1/sources/DST/flex/flex-2.5.11.tar.gz
 
+# flex 2.5.14
+get_file http://download.nust.na/pub2/openpkg1/sources/DST/flex/flex-2.5.14.tar.gz
+
 # General cleanup
 find tmp -name .git -exec rm -rf \;
 
diff --git a/sysa/flex-2.5.14/flex-2.5.14.sh b/sysa/flex-2.5.14/flex-2.5.14.sh
new file mode 100755
index 0000000..edf31de
--- /dev/null
+++ b/sysa/flex-2.5.14/flex-2.5.14.sh
@@ -0,0 +1,6 @@
+src_prepare() {
+    default_src_prepare
+
+    touch config.h
+    rm parse.c parse.h scan.c
+}
diff --git a/sysa/flex-2.5.14/mk/main.mk b/sysa/flex-2.5.14/mk/main.mk
new file mode 100644
index 0000000..caf85a2
--- /dev/null
+++ b/sysa/flex-2.5.14/mk/main.mk
@@ -0,0 +1,29 @@
+CFLAGS =    -I . \
+            -DVERSION=\"2.5.14\"
+
+all: flex
+
+flex: ccl.o dfa.o ecs.o gen.o main.o misc.o nfa.o parse.o scan.o skel.o sym.o tblcmp.o yylex.o options.o scanopt.o buf.o
+	tcc -o $@ $^
+
+%.o: %.c
+	tcc -g -c $(CFLAGS) -o $@ $<
+
+scan.o: parse.h
+yylex.o: parse.h
+
+parse.c parse.h: parse.y
+	yacc -d parse.y
+	mv y.tab.h parse.h
+	mv y.tab.c parse.c
+
+scan.c: scan.l
+	flex scan.l
+	mv lex.yy.c scan.c
+
+skel.c: mkskel.sh flex.skl
+	/bin/sh ./mkskel.sh ./flex.skl > skel.c
+
+install: all
+	install flex $(PREFIX)/bin
+	ln -sf $(PREFIX)/bin/flex $(PREFIX)/bin/lex
diff --git a/sysa/flex-2.5.14/src/.placeholder b/sysa/flex-2.5.14/src/.placeholder
new file mode 100644
index 0000000..e69de29
diff --git a/sysa/run.sh b/sysa/run.sh
index d5ecd18..579ab88 100755
--- a/sysa/run.sh
+++ b/sysa/run.sh
@@ -14,6 +14,8 @@ build m4-1.4
 
 # Part 22
 build flex-2.5.11
-build flex-2.5.11
+
+# Part 23
+build flex-2.5.14
 
 echo "Bootstrapping completed."