diff --git a/INSTALL.md b/INSTALL.md
index 6a3bec9..cc7b916 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -5,7 +5,7 @@ Only dependency is C library and POSIX getopt support.
 
 Compiling with GCC or CLANG:
 
-    cc -std=gnu99 -Wpedantic -Wall -Wextra -Os -s -o mcrcon mcrcon.c
+    cc -std=gnu99 -Wpedantic -Wall -Wextra -O2 -o mcrcon mcrcon.c
     
 Note: on Windows remember to link with winsock by adding `-lws2_32` to your compiler command line.
 
diff --git a/Makefile b/Makefile
index c755128..25b5127 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@
 #   make
 #
 # Windows cross compile:
-#   i686-w64-mingw32-gcc -std=gnu99 -Wall -Wextra -Wpedantic -Os -s -o mcrcon.exe mcrcon.c -lws2_32
+#   i686-w64-mingw32-gcc -std=gnu99 -Wall -Wextra -Wpedantic -O2 -o mcrcon.exe mcrcon.c -lws2_32
 
 EXENAME = mcrcon
 PREFIX ?= /usr/local
@@ -14,8 +14,8 @@ LINKER =
 RM = rm -v -f
 
 CC = gcc
-CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -Os -s
-EXTRAFLAGS ?= -fstack-protector-strong
+CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -O2
+EXTRAFLAGS ?= -fstack-protector-all
 
 ifeq ($(OS), Windows_NT)
 	LINKER = -lws2_32
@@ -25,7 +25,7 @@ endif
 
 ifeq ($(shell uname), Darwin)
 	INSTALL = ginstall
-	CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -Os
+	CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -O2
 endif
 
 .PHONY: all