diff --git a/2019/endoh/Makefile b/2019/endoh/Makefile
index 473de4155..d8b26d3f5 100644
--- a/2019/endoh/Makefile
+++ b/2019/endoh/Makefile
@@ -65,7 +65,9 @@ CINCLUDE=
 
 # Optimization
 #
-OPT=
+# We disable the optimiser and we enable -g because the entry is A BACKTRACE
+# QUINE and NEEDS debugging symbols.
+OPT= -O0 -g
 
 # Default flags for ANSI C compilation
 #
@@ -129,8 +131,11 @@ all: data ${TARGET}
 	clean clobber install love haste waste maker easter_egg \
 	sandwich supernova deep_magic magic charon pluto
 
+# We FORCE the use of -O0 -g even if someone overrides it because this entry is
+# a BACKTRACE QUINE and NEEDS debugging symbols.
+#
 ${PROG}: ${PROG}.c
-	${CC} ${CFLAGS} -g $< -o $@ ${LDFLAGS}
+	${CC} ${CFLAGS} -O0 -g $< -o $@ ${LDFLAGS}
 
 ascii: ascii.c
 	${CC} $< -o $@
diff --git a/2019/endoh/README.md b/2019/endoh/README.md
index b4ce509d8..e13f45560 100644
--- a/2019/endoh/README.md
+++ b/2019/endoh/README.md
@@ -4,6 +4,9 @@
 make
 ```
 
+NOTE: the use of the C compiler optimiser was disabled and `-g` was enabled for
+this entry because it is SUPPOSED to crash and it needs debugging symbols.
+
 
 ### Bugs and (Mis)features: