diff --git a/Makefile b/Makefile
index f9710f7..8c41ab1 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,8 @@ INCLUDEDIR := include
 
 KSRC := $(wildcard kernel/*.asm kernel/*.c)
 KOBJ := $(addprefix $(BUILDDIR)/, \
-		$(notdir \
-		$(patsubst %.asm,%.o, $(patsubst %.c,%.o, $(KSRC)))))
+	$(notdir \
+	$(patsubst %.asm,%.o, $(patsubst %.c,%.o, $(KSRC)))))
 KIMG := kernel.bin
 
 ISO := Hazel.iso
@@ -27,6 +27,7 @@ $(BUILDDIR)/%.o: */%.c
 kernel: $(BUILDDIR)/$(KIMG)
 
 $(BUILDDIR)/$(ISO): kernel
+	rm -f $(BUILDDIR)/$(ISO)
 	cp $(BUILDDIR)/$(KIMG) boot/$(KIMG)
 	grub-mkrescue -o  $(BUILDDIR)/$(ISO) .
 iso: $(BUILDDIR)/$(ISO)
@@ -34,4 +35,4 @@ iso: $(BUILDDIR)/$(ISO)
 qemu: iso
 	qemu-system-i386 $(QEMUFLAGS)
 clean:
-	rm build/* boot/*.bin
+	rm -f build/* boot/*.bin
diff --git a/include/kernel/kernel.h b/include/kernel/kernel.h
index 77d2237..263199f 100644
--- a/include/kernel/kernel.h
+++ b/include/kernel/kernel.h
@@ -5,6 +5,7 @@
 #include <kernel/log.h>
 
 #define cpu_relax asm volatile ("pause" ::)
+#define CHECK_FLAG(x, n) (x & (1<<n))
 
 typedef struct {
    multiboot_memory_map_t *mem_map;
diff --git a/kernel/kernel.c b/kernel/kernel.c
index aec5a06..97aa1b0 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -5,13 +5,12 @@
 kernel_ctx_t ctx = {0};
 
 void kernel(multiboot_info_t *info) {
-    if (!(info->flags & (1<<6))) goto halt;
-    if (!(info->flags & (1<<12))) goto halt;
+    if (!CHECK_FLAG(info->flags, 6)) goto halt;  // Memory map
+    if (!CHECK_FLAG(info->flags, 12)) goto halt; // VBE data 
     ctx.mem_map = (multiboot_memory_map_t *)info->memmapaddress;
     ctx.mem_map_len = info->memmaplength;
 
-    if (serial_port_init(COM1))
-	ctx.log_method = LOG_COM1;
+    if (serial_port_init(COM1)) ctx.log_method = LOG_COM1;
 
     LOG("Kernel log being sent to COM1\n");
 halt: