diff --git a/components/bootloader/Makefile.projbuild b/components/bootloader/Makefile.projbuild
index 559769957..02135e1c6 100644
--- a/components/bootloader/Makefile.projbuild
+++ b/components/bootloader/Makefile.projbuild
@@ -11,7 +11,7 @@
 ifeq ("$(IS_BOOTLOADER_BUILD)","")
 
 BOOTLOADER_COMPONENT_PATH := $(COMPONENT_PATH)
-BOOTLOADER_BUILD_DIR=$(BUILD_DIR_BASE)/bootloader
+BOOTLOADER_BUILD_DIR=$(abspath $(BUILD_DIR_BASE)/bootloader)
 BOOTLOADER_BIN=$(BOOTLOADER_BUILD_DIR)/bootloader.bin
 BOOTLOADER_SDKCONFIG=$(BOOTLOADER_BUILD_DIR)/sdkconfig
 
diff --git a/components/esp32/component.mk b/components/esp32/component.mk
index 85040d77a..b3d95f1b1 100644
--- a/components/esp32/component.mk
+++ b/components/esp32/component.mk
@@ -6,7 +6,7 @@
 # lib(subdirectory_name).a in the build directory. This behaviour is entirely configurable,
 # please read the esp-idf build system document if you need to do this.
 #
--include $(BUILD_DIR_BASE)/include/config/auto.conf
+-include include/config/auto.conf
 
 COMPONENT_SRCDIRS := . hwcrypto
 
diff --git a/make/project.mk b/make/project.mk
index 74943334a..c4bf68db6 100644
--- a/make/project.mk
+++ b/make/project.mk
@@ -106,7 +106,7 @@ COMPONENT_INCLUDES := $(abspath $(foreach comp,$(COMPONENT_PATHS_BUILDABLE),$(ad
 	$(call GetVariable,$(comp),COMPONENT_ADD_INCLUDEDIRS))))
 
 #Also add project include path, for sdk includes
-COMPONENT_INCLUDES += $(BUILD_DIR_BASE)/include/
+COMPONENT_INCLUDES += $(abspath $(BUILD_DIR_BASE)/include/)
 export COMPONENT_INCLUDES
 
 #COMPONENT_LDFLAGS has a list of all flags that are needed to link the components together. It's collected
diff --git a/make/project_config.mk b/make/project_config.mk
index 40f51ff8f..00452dda4 100644
--- a/make/project_config.mk
+++ b/make/project_config.mk
@@ -18,7 +18,7 @@ $(KCONFIG_TOOL_DIR)/mconf $(KCONFIG_TOOL_DIR)/conf:
 	$(MAKE) -C $(KCONFIG_TOOL_DIR)
 
 # use a wrapper environment for where we run Kconfig tools
-KCONFIG_TOOL_ENV=KCONFIG_AUTOHEADER=$(BUILD_DIR_BASE)/include/sdkconfig.h \
+KCONFIG_TOOL_ENV=KCONFIG_AUTOHEADER=$(abspath $(BUILD_DIR_BASE)/include/sdkconfig.h) \
 	COMPONENT_KCONFIGS="$(COMPONENT_KCONFIGS)" KCONFIG_CONFIG=$(SDKCONFIG) \
 	COMPONENT_KCONFIGS_PROJBUILD="$(COMPONENT_KCONFIGS_PROJBUILD)"
 
diff --git a/make/test_build_system.sh b/make/test_build_system.sh
index 401c8376c..b7004eece 100755
--- a/make/test_build_system.sh
+++ b/make/test_build_system.sh
@@ -91,7 +91,7 @@ function run_tests()
 		 failure "Files weren't cleaned: ${ALL_BUILD_FILES}"
 	fi
 
-	print_status "Moving BUILD_DIR_BASE out of tree should still build OK"
+	print_status "Moving BUILD_DIR_BASE out of tree"
 	rm -rf --preserve-root ${BUILD}/*
 	OUTOFTREE_BUILD=${TESTDIR}/alt_build
 	make BUILD_DIR_BASE=${OUTOFTREE_BUILD} || failure "Failed to build with BUILD_DIR_BASE overriden"
@@ -104,6 +104,14 @@ function run_tests()
 		failure "Some files were incorrectly put into the default build directory: ${DEFAULT_BUILD_FILES}"
 	fi
 
+	print_status "BUILD_DIR_BASE inside default build directory"
+	rm -rf --preserve-root ${BUILD}/*
+	make BUILD_DIR_BASE=build/subdirectory || failure "Failed to build with BUILD_DIR_BASE as subdir"
+	NEW_BUILD_FILES=$(find ${BUILD}/subdirectory -type f)
+	if [ -z "${NEW_BUILD_FILES}" ]; then
+		failure "No files found in new build directory!"
+	fi
+
 	print_status "Can still clean build if all text files are CRLFs"
 	make clean || failure "Unexpected failure to make clean"
 	find . -exec unix2dos {} \; # CRLFify template dir