diff --git a/src/kernel/Jmk b/src/kernel/Jmk
index 05e2b8e..eefaa34 100644
--- a/src/kernel/Jmk
+++ b/src/kernel/Jmk
@@ -24,7 +24,7 @@
 
 FS ?= ext2
 
-CFLAGS += -I $(ROOT)/include/kernel $(test_defines)
+CFLAGS += -I $(ROOT)/include/kernel $(test_defines) -O0
 
 LDFLAGS += -Tlink.ld -melf_i386
 ASMFLAGS += -felf -Fdwarf