diff --git a/arch/x86_64/extra.mk b/arch/x86_64/extra.mk
index 0b298bf..db2a407 100644
--- a/arch/x86_64/extra.mk
+++ b/arch/x86_64/extra.mk
@@ -1,29 +1,29 @@
 QEMU := qemu-system-x86_64
 QEMU_FLAGS := -m 64M -smp 4
 
-ARCH_TEMP_FILES := $(BUILDDIR)/$(KERNEL_EXEC).elf32
+ARCH_TEMP_FILES := $(BUILD_DIR)/$(KERNEL_EXEC).elf32
 
 # qemu refuses to boot ELF64 binaries. this creates a patched version of the kernel
 # binary to trick qemu into thinking its an ELF32.
 # this has no effect on the kernel itself; the x86_64 kernel's
 # entry point is 32-bit machine code.
-$(BUILDDIR)/$(KERNEL_EXEC).elf32: $(BUILDDIR)/$(KERNEL_EXEC)
-	@cp $(BUILDDIR)/$(KERNEL_EXEC) $(BUILDDIR)/$(KERNEL_EXEC).elf32
-	@printf '\x03\x00' | dd of=$(BUILDDIR)/$(KERNEL_EXEC).elf32 bs=1 seek=18 count=2 conv=notrunc 2> /dev/null
+$(BUILD_DIR)/$(KERNEL_EXEC).elf32: $(BUILD_DIR)/$(KERNEL_EXEC)
+	@cp $(BUILD_DIR)/$(KERNEL_EXEC) $(BUILD_DIR)/$(KERNEL_EXEC).elf32
+	@printf '\x03\x00' | dd of=$(BUILD_DIR)/$(KERNEL_EXEC).elf32 bs=1 seek=18 count=2 conv=notrunc 2> /dev/null
 
-run: $(BUILDDIR)/$(KERNEL_EXEC) $(BUILDDIR)/$(KERNEL_EXEC).elf32
+run: $(BUILD_DIR)/$(KERNEL_EXEC) $(BUILD_DIR)/$(KERNEL_EXEC).elf32
 	@echo "    \033[1;93mBOOT\033[0m   $<"
 
-	@$(QEMU) -kernel $(BUILDDIR)/$(KERNEL_EXEC).elf32
+	@$(QEMU) -kernel $(BUILD_DIR)/$(KERNEL_EXEC).elf32
 
-debug: $(BUILDDIR)/$(KERNEL_EXEC) $(BUILDDIR)/$(KERNEL_EXEC).elf32
+debug: $(BUILD_DIR)/$(KERNEL_EXEC) $(BUILD_DIR)/$(KERNEL_EXEC).elf32
 	@echo "    \033[1;93mDEBUG\033[0m  $<"
 
 	@./tools/kernel-debug/debug_session.sh \
 		tools/kernel-debug/gdb_session_init \
 		tools/kernel-debug/lldb_session_init \
 		$(QEMU) \
-			-kernel $(BUILDDIR)/$(KERNEL_EXEC).elf32 -S -s \
-			-curses -serial file:socks.log $(QEMU_FLAGS)
+			-kernel $(BUILD_DIR)/$(KERNEL_EXEC).elf32 -S -s \
+			-curses -serial file:$(BUILD_DIR)/socks.log $(QEMU_FLAGS)