diff --git a/Makefile b/Makefile
index 59d996f..746c92e 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ GCC_PREF=riscv32-unknown-elf-
 
 CC=$(GCC_PREF)gcc
 OBJDUMP=$(GCC_PREF)objdump
-CFLAGS=-I$(KLIBDIR) -O3 -MD -mcmodel=medany -Wall -Wextra -pedantic-errors -Wno-builtin-declaration-mismatch
+CFLAGS=-I$(KLIBDIR) -MD -mcmodel=medany -Wall -Wextra -pedantic-errors -Wno-builtin-declaration-mismatch
 KERNEL_CFLAGS=-nostdlib -T linker.ld
 ARCH = rv32im