diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ab96515..8998c98 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -76,15 +76,12 @@ jobs:
         run: |
           make TOIT_VERSION=${{ github.event.inputs.toit-version }} download-toit
 
-      - name: Build the host SDK
-        run: |
-          make build-host
-
-      - name: Install ESP32 tools
+      - name: Patch Toit
         run: |
-          toit/third_party/esp-idf/install.sh
+          # Temporary patch until upstream is fixed.
+          (cd toit && patch -p1 < ../patches/toit.patch)
 
-      - name: Build tool
+      - name: Build the host SDK
         env:
           IDF_CCACHE_ENABLE: 1
           CCACHE_DIR: ${{ github.workspace }}/.ccache
@@ -92,6 +89,14 @@ jobs:
           CCACHE_COMPRESS: true
           CCACHE_COMPRESSLEVEL: '6'
           CCACHE_MAXSIZE: 800M
+        run: |
+          make build-host
+
+      - name: Install ESP32 tools
+        run: |
+          toit/third_party/esp-idf/install.sh
+
+      - name: Build tool
         run: |
           build/host/sdk/bin/toit.compile -o build/env-tool tools/main.toit
 
diff --git a/patches/toit.patch b/patches/toit.patch
new file mode 100644
index 0000000..e385fdc
--- /dev/null
+++ b/patches/toit.patch
@@ -0,0 +1,260 @@
+diff --git a/Makefile b/Makefile
+index 1d704aa4..20e3791a 100644
+--- a/Makefile
++++ b/Makefile
+@@ -18,8 +18,9 @@
+ SHELL=bash
+ 
+ # General options.
+-HOST=host
+-BUILD_TYPE=Release
++BUILD ?= build
++HOST ?= host
++BUILD_TYPE ?= Release
+ TARGET ?= $(HOST)
+ TOOLCHAIN ?= $(TARGET)
+ 
+@@ -94,58 +95,58 @@ endif
+ # cmake needs to be rerun, but we don't detect that, so it might not
+ # get run enough.  It takes <1s on Linux to run cmake, so it's
+ # usually best to run it eagerly.
+-.PHONY: build/$(TARGET)/CMakeCache.txt
+-build/$(TARGET)/CMakeCache.txt:
++.PHONY: $(BUILD)/$(TARGET)/CMakeCache.txt
++$(BUILD)/$(TARGET)/CMakeCache.txt:
+ 	$(MAKE) rebuild-cmake
+ 
+ ifneq ($(TARGET),$(HOST))
+ # Support for cross-compilation.
+ 
+-.PHONY: build/$(HOST)/CMakeCache.txt
+-build/$(HOST)/CMakeCache.txt:
++.PHONY: $(BUILD)/$(HOST)/CMakeCache.txt
++$(BUILD)/$(HOST)/CMakeCache.txt:
+ 	$(MAKE) TARGET=$(HOST) rebuild-cmake
+ 
+ .PHONY: sysroot
+ sysroot: check-env
+-	$(MAKE) build/$(TARGET)/sysroot/usr
++	$(MAKE) $(BUILD)/$(TARGET)/sysroot/usr
+ endif
+ 
+-BIN_DIR = $(CURDIR)/build/$(HOST)/sdk/bin
++BIN_DIR = $(abspath $(BUILD)/$(HOST)/sdk/bin)
+ TOITPKG_BIN = $(BIN_DIR)/toit.pkg$(EXE_SUFFIX)
+ TOITC_BIN = $(BIN_DIR)/toit.compile$(EXE_SUFFIX)
+ FIRMWARE_BIN = $(TOIT_TOOLS_DIR)/firmware$(EXE_SUFFIX)
+ 
+ .PHONY: download-packages
+-download-packages: check-env build/$(HOST)/CMakeCache.txt tools
+-	(cd build/$(HOST) && ninja download_packages)
++download-packages: check-env $(BUILD)/$(HOST)/CMakeCache.txt tools
++	(cd $(BUILD)/$(HOST) && ninja download_packages)
+ 
+ .PHONY: rebuild-cmake
+ rebuild-cmake:
+-	mkdir -p build/$(TARGET)
+-	(cd build/$(TARGET) && cmake ../../ -G Ninja -DTOITC=$(TOITC_BIN) -DTOITPKG=$(TOITPKG_BIN) -DCMAKE_BUILD_TYPE=$(BUILD_TYPE) -DCMAKE_TOOLCHAIN_FILE=../../toolchains/$(TOOLCHAIN).cmake --no-warn-unused-cli)
++	mkdir -p $(BUILD)/$(TARGET)
++	(cd $(BUILD)/$(TARGET) && cmake $(CURDIR) -G Ninja -DTOITC=$(TOITC_BIN) -DTOITPKG=$(TOITPKG_BIN) -DCMAKE_BUILD_TYPE=$(BUILD_TYPE) -DCMAKE_TOOLCHAIN_FILE=$(CURDIR)/toolchains/$(TOOLCHAIN).cmake --no-warn-unused-cli)
+ 
+ .PHONY: host-tools
+-host-tools: check-env build/$(HOST)/CMakeCache.txt
+-	(cd build/$(HOST) && ninja build_tools)
++host-tools: check-env $(BUILD)/$(HOST)/CMakeCache.txt
++	(cd $(BUILD)/$(HOST) && ninja build_tools)
+ 
+ .PHONY: tools
+ # This rule contains a reference to host-tools.
+ # This means that on host we will try to build host twice, but
+ # the second attempt will be a no-op.
+-tools: host-tools check-env build/$(TARGET)/CMakeCache.txt
+-	(cd build/$(TARGET) && ninja build_tools)
++tools: host-tools check-env $(BUILD)/$(TARGET)/CMakeCache.txt
++	(cd $(BUILD)/$(TARGET) && ninja build_tools)
+ 
+ .PHONY: toit-tools
+ toit-tools: tools download-packages
+-	(cd build/$(TARGET) && ninja build_toit_tools)
++	(cd $(BUILD)/$(TARGET) && ninja build_toit_tools)
+ 
+ .PHONY: vessels
+-vessels: check-env build/$(TARGET)/CMakeCache.txt
+-	(cd build/$(TARGET) && ninja build_vessels)
++vessels: check-env $(BUILD)/$(TARGET)/CMakeCache.txt
++	(cd $(BUILD)/$(TARGET) && ninja build_vessels)
+ 
+ .PHONY: version-file
+-version-file: build/$(TARGET)/CMakeCache.txt
+-	(cd build/$(TARGET) && ninja build_version_file)
++version-file: $(BUILD)/$(TARGET)/CMakeCache.txt
++	(cd $(BUILD)/$(TARGET) && ninja build_version_file)
+ 
+ 
+ .PHONY: pi
+@@ -157,17 +158,17 @@ SYSROOT_URL=https://github.com/toitlang/sysroots/releases/download/v1.3.0/sysroo
+ 
+ rebuild-cmake: sysroot
+ 
+-build/$(TARGET)/sysroot/sysroot.tar.xz:
++$(BUILD)/$(TARGET)/sysroot/sysroot.tar.xz:
+ 	if [[ "$(SYSROOT_URL)" == "" ]]; then \
+ 		echo "No sysroot URL for $(TARGET)"; \
+ 		exit 1; \
+ 	fi
+ 
+-	mkdir -p build/$(TARGET)/sysroot
+-	curl --location --output build/$(TARGET)/sysroot/sysroot.tar.xz $(SYSROOT_URL)
++	mkdir -p $(BUILD)/$(TARGET)/sysroot
++	curl --location --output $(BUILD)/$(TARGET)/sysroot/sysroot.tar.xz $(SYSROOT_URL)
+ 
+-build/$(TARGET)/sysroot/usr: build/$(TARGET)/sysroot/sysroot.tar.xz
+-	tar x -f build/$(TARGET)/sysroot/sysroot.tar.xz -C build/$(TARGET)/sysroot
++$(BUILD)/$(TARGET)/sysroot/usr: $(BUILD)/$(TARGET)/sysroot/sysroot.tar.xz
++	tar x -f $(BUILD)/$(TARGET)/sysroot/sysroot.tar.xz -C $(BUILD)/$(TARGET)/sysroot
+ 	touch $@
+ endif
+ 
+@@ -196,7 +197,7 @@ esp32:
+ 
+ .PHONY: esp32-no-env
+ esp32-no-env: check-env check-esp32-env sdk
+-	cmake -E env IDF_TARGET=$(IDF_TARGET) IDF_CCACHE_ENABLE=1 python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B build/$(ESP32_CHIP) -p "$(ESP32_PORT)" build
++	cmake -E env IDF_TARGET=$(IDF_TARGET) IDF_CCACHE_ENABLE=1 python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B $(BUILD)/$(ESP32_CHIP) -p "$(ESP32_PORT)" build
+ 
+ # ESP32 MENU CONFIG
+ .PHONY: menuconfig
+@@ -206,7 +207,7 @@ menuconfig:
+ 
+ .PHONY: menuconfig-no-env
+ menuconfig-no-env: check-env check-esp32-env
+-	cmake -E env IDF_TARGET=$(IDF_TARGET) python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B build/$(ESP32_CHIP) -p "$(ESP32_PORT)" menuconfig
++	cmake -E env IDF_TARGET=$(IDF_TARGET) python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B $(BUILD)/$(ESP32_CHIP) -p "$(ESP32_PORT)" menuconfig
+ 
+ .PHONY: flash
+ flash:
+@@ -215,21 +216,21 @@ flash:
+ 
+ .PHONY: flash-no-env
+ flash-no-env: esp32-no-env
+-	cmake -E env IDF_TARGET=$(IDF_TARGET) python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B build/$(ESP32_CHIP) -p "$(ESP32_PORT)" flash monitor
++	cmake -E env IDF_TARGET=$(IDF_TARGET) python$(EXE_SUFFIX) $(IDF_PY) -C toolchains/$(ESP32_CHIP) -B $(BUILD)/$(ESP32_CHIP) -p "$(ESP32_PORT)" flash monitor
+ 
+ # UTILITY
+ .PHONY:	clean
+ clean:
+-	rm -rf build/
++	rm -rf $(BUILD)/
+ 	find toolchains -name sdkconfig -exec rm '{}' ';'
+ 
+ INSTALL_SRC_ARCH := $(TARGET)
+ 
+ .PHONY: install-sdk install
+ install-sdk:
+-	install -D --target-directory="$(DESTDIR)$(prefix)"/bin "$(CURDIR)"/build/$(INSTALL_SRC_ARCH)/sdk/bin/*
+-	install -D --target-directory="$(DESTDIR)$(prefix)"/tools "$(CURDIR)"/build/$(INSTALL_SRC_ARCH)/sdk/tools/*
+-	install -D --target-directory="$(DESTDIR)$(prefix)"/vessels "$(CURDIR)"/build/$(INSTALL_SRC_ARCH)/sdk/vessels/*
++	install -D --target-directory="$(DESTDIR)$(prefix)"/bin "$(BUILD)"/$(INSTALL_SRC_ARCH)/sdk/bin/*
++	install -D --target-directory="$(DESTDIR)$(prefix)"/tools "$(BUILD)"/$(INSTALL_SRC_ARCH)/sdk/tools/*
++	install -D --target-directory="$(DESTDIR)$(prefix)"/vessels "$(BUILD)"/$(INSTALL_SRC_ARCH)/sdk/vessels/*
+ 	mkdir -p "$(DESTDIR)$(prefix)"/lib
+ 	cp -R "$(CURDIR)"/lib/* "$(DESTDIR)$(prefix)"/lib
+ 	find "$(DESTDIR)$(prefix)"/lib -type f -exec chmod 644 {} \;
+@@ -240,41 +241,41 @@ install: install-sdk
+ # TESTS (host)
+ .PHONY: test
+ test:
+-	(cd build/$(HOST) && ninja check_slow check_fuzzer_lib)
++	(cd $(BUILD)/$(HOST) && ninja check_slow check_fuzzer_lib)
+ 
+ .PHONY: test-fast
+ test-fast:
+-	(cd build/$(HOST) && ninja check)
++	(cd $(BUILD)/$(HOST) && ninja check)
+ 
+ .PHONY: update-gold
+ update-gold:
+ 	$(MAKE) rebuild-cmake
+-	(cd build/$(HOST) && ninja update_gold)
+-	(cd build/$(HOST) && ninja update_minus_s_gold)
+-	(cd build/$(HOST) && ninja update_type_gold)
++	(cd $(BUILD)/$(HOST) && ninja update_gold)
++	(cd $(BUILD)/$(HOST) && ninja update_minus_s_gold)
++	(cd $(BUILD)/$(HOST) && ninja update_type_gold)
+ 
+ .PHONY: test-health
+ test-health: download-packages
+ 	$(MAKE) rebuild-cmake
+-	(cd build/$(HOST) && ninja check_health)
++	(cd $(BUILD)/$(HOST) && ninja check_health)
+ 
+ .PHONY: update-health-gold
+ update-health-gold: download-packages
+ 	$(MAKE) rebuild-cmake
+-	(cd build/$(HOST) && ninja clear_health_gold)
+-	(cd build/$(HOST) && ninja update_health_gold)
++	(cd $(BUILD)/$(HOST) && ninja clear_health_gold)
++	(cd $(BUILD)/$(HOST) && ninja update_health_gold)
+ 
+ .PHONY: enable-external
+ enable-external:
+ 	$(MAKE) rebuild-cmake  # Ensure the cmake-directory was created.
+-	cmake -DTOIT_TEST_EXTERNAL=ON build/$(HOST)
++	cmake -DTOIT_TEST_EXTERNAL=ON $(BUILD)/$(HOST)
+ 	$(MAKE) download-external
+ 	$(MAKE) rebuild-cmake
+ 	$(MAKE) download-packages
+ 
+ .PHONY: check-external-enabled
+ check-external-enabled:
+-	@ if ! cmake -LA -N build/$(HOST) | grep 'TOIT_TEST_EXTERNAL:BOOL=ON'; then \
++	@ if ! cmake -LA -N $(BUILD)/$(HOST) | grep 'TOIT_TEST_EXTERNAL:BOOL=ON'; then \
+ 		echo "external projects are not enabled. Run 'make enable-external' first."; \
+ 		exit 1; \
+ 	fi
+@@ -282,23 +283,23 @@ check-external-enabled:
+ .PHONY: disable-external
+ disable-external: check-external-enabled
+ 	$(MAKE) rebuild-cmake  # Ensure the cmake-directory was created.
+-	cmake -DTOIT_TEST_EXTERNAL=OFF build/$(HOST)
++	cmake -DTOIT_TEST_EXTERNAL=OFF $(BUILD)/$(HOST)
+ 
+ .PHONY: download-external
+ download-external: check-external-enabled
+ 	# Download with higher parallelism.
+-	(cd build/$(HOST) && ninja -j 16 download_external)
++	(cd $(BUILD)/$(HOST) && ninja -j 16 download_external)
+ 
+ .PHONY: test-external
+ test-external: check-external-enabled
+-	(cd build/$(HOST) && ninja check_external)
++	(cd $(BUILD)/$(HOST) && ninja check_external)
+ 
+ .PHONY: test-external-health
+ test-external-health: check-external-enabled
+-	(cd build/$(HOST) && ninja check_external_health)
++	(cd $(BUILD)/$(HOST) && ninja check_external_health)
+ 
+ .PHONY: update-external-health-gold
+ update-external-health-gold: download-packages check-external-enabled
+ 	$(MAKE) rebuild-cmake
+-	(cd build/$(HOST) && ninja clear_external_health_gold)
+-	(cd build/$(HOST) && ninja update_external_health_gold)
++	(cd $(BUILD)/$(HOST) && ninja clear_external_health_gold)
++	(cd $(BUILD)/$(HOST) && ninja update_external_health_gold)
+diff --git a/toolchains/idf/components/toit/CMakeLists.txt b/toolchains/idf/components/toit/CMakeLists.txt
+index 894d9069..a1cba859 100644
+--- a/toolchains/idf/components/toit/CMakeLists.txt
++++ b/toolchains/idf/components/toit/CMakeLists.txt
+@@ -12,7 +12,10 @@ set(TOIT_SYSTEM_NAME "esp32")
+ 
+ set(TOIT_INTERPRETER_FLAGS "-fno-crossjumping;-fno-tree-tail-merge" CACHE STRING "toit interpreter flags")
+ 
+-set(TOIT_SDK_DIR ${TOIT_BASE_DIR}/build/host/sdk)
++# If TOIT_SDK_DIR is not set, do it now.
++if (NOT TOIT_SDK_DIR)
++    set(TOIT_SDK_DIR ${TOIT_BASE_DIR}/build/host/sdk)
++endif()
+ set(TOIT_SDK_DIR ${TOIT_SDK_DIR} PARENT_SCOPE)
+ set(TOITC ${TOIT_SDK_DIR}/bin/toit.compile)
+ set(TOITPKG ${TOIT_SDK_DIR}/bin/toit.pkg)