diff --git a/ports/esp32/Makefile b/ports/esp32/Makefile
index 3e48febf0..25001643e 100644
--- a/ports/esp32/Makefile
+++ b/ports/esp32/Makefile
@@ -50,7 +50,13 @@ SDKCONFIG_COMBINED = $(BUILD)/sdkconfig.combined
 SDKCONFIG_H = $(BUILD)/sdkconfig.h
 
 # the git hash of the currently supported ESP IDF version
-ESPIDF_SUPHASH := 6ccb4cf5b7d1fdddb8c2492f9cbc926abaf230df
+ESPIDF_SUPHASH_V3 := 6ccb4cf5b7d1fdddb8c2492f9cbc926abaf230df
+ESPIDF_SUPHASH_V4 := 310beae373446ceb9a4ad9b36b5428d7fdf2705f
+
+define print_supported_git_hash
+$(info Supported git hash (v3.3): $(ESPIDF_SUPHASH_V3))
+$(info Supported git hash (v4.0-beta1) (experimental): $(ESPIDF_SUPHASH_V4))
+endef
 
 # paths to ESP IDF and its components
 ifeq ($(ESPIDF),)
@@ -59,10 +65,11 @@ ESPIDF = $(IDF_PATH)
 else
 $(info The ESPIDF variable has not been set, please set it to the root of the esp-idf repository.)
 $(info See README.md for installation instructions.)
-$(info Supported git hash: $(ESPIDF_SUPHASH))
 $(error ESPIDF not set)
+print_supported_git_hash
 endif
 endif
+
 ESPCOMP = $(ESPIDF)/components
 ESPTOOL ?= $(ESPCOMP)/esptool_py/esptool/esptool.py
 ESPCOMP_KCONFIGS = $(shell find $(ESPCOMP) -name Kconfig)
@@ -70,13 +77,18 @@ ESPCOMP_KCONFIGS_PROJBUILD = $(shell find $(ESPCOMP) -name Kconfig.projbuild)
 
 # verify the ESP IDF version
 ESPIDF_CURHASH := $(shell git -C $(ESPIDF) show -s --pretty=format:'%H')
-ifneq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH))
+
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V3))
+$(info Building with ESP IDF v3)
+else ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+$(info Building with ESP IDF v4)
+else
 $(info ** WARNING **)
 $(info The git hash of ESP IDF does not match the supported version)
 $(info The build may complete and the firmware may work but it is not guaranteed)
 $(info ESP IDF path:       $(ESPIDF))
 $(info Current git hash:   $(ESPIDF_CURHASH))
-$(info Supported git hash: $(ESPIDF_SUPHASH))
+print_supported_git_hash
 endif
 
 # pretty format of ESP IDF version, used internally by the IDF
@@ -100,20 +112,13 @@ INC_ESPCOMP += -I$(ESPCOMP)/bootloader_support/include_bootloader
 INC_ESPCOMP += -I$(ESPCOMP)/console
 INC_ESPCOMP += -I$(ESPCOMP)/driver/include
 INC_ESPCOMP += -I$(ESPCOMP)/driver/include/driver
-INC_ESPCOMP += -I$(ESPCOMP)/nghttp/port/include
-INC_ESPCOMP += -I$(ESPCOMP)/nghttp/nghttp2/lib/includes
 INC_ESPCOMP += -I$(ESPCOMP)/efuse/include
 INC_ESPCOMP += -I$(ESPCOMP)/efuse/esp32/include
 INC_ESPCOMP += -I$(ESPCOMP)/esp32/include
 INC_ESPCOMP += -I$(ESPCOMP)/espcoredump/include
 INC_ESPCOMP += -I$(ESPCOMP)/soc/include
 INC_ESPCOMP += -I$(ESPCOMP)/soc/esp32/include
-INC_ESPCOMP += -I$(ESPCOMP)/ethernet/include
-INC_ESPCOMP += -I$(ESPCOMP)/expat/expat/expat/lib
-INC_ESPCOMP += -I$(ESPCOMP)/expat/port/include
 INC_ESPCOMP += -I$(ESPCOMP)/heap/include
-INC_ESPCOMP += -I$(ESPCOMP)/json/include
-INC_ESPCOMP += -I$(ESPCOMP)/json/port/include
 INC_ESPCOMP += -I$(ESPCOMP)/log/include
 INC_ESPCOMP += -I$(ESPCOMP)/newlib/platform_include
 INC_ESPCOMP += -I$(ESPCOMP)/newlib/include
@@ -129,20 +134,41 @@ INC_ESPCOMP += -I$(ESPCOMP)/mbedtls/mbedtls/include
 INC_ESPCOMP += -I$(ESPCOMP)/mbedtls/port/include
 INC_ESPCOMP += -I$(ESPCOMP)/mdns/include
 INC_ESPCOMP += -I$(ESPCOMP)/mdns/private_include
-INC_ESPCOMP += -I$(ESPCOMP)/micro-ecc/micro-ecc
 INC_ESPCOMP += -I$(ESPCOMP)/spi_flash/include
 INC_ESPCOMP += -I$(ESPCOMP)/ulp/include
 INC_ESPCOMP += -I$(ESPCOMP)/vfs/include
 INC_ESPCOMP += -I$(ESPCOMP)/xtensa-debug-module/include
 INC_ESPCOMP += -I$(ESPCOMP)/wpa_supplicant/include
 INC_ESPCOMP += -I$(ESPCOMP)/wpa_supplicant/port/include
-INC_ESPCOMP += -I$(ESPCOMP)/ethernet/include
 INC_ESPCOMP += -I$(ESPCOMP)/app_trace/include
 INC_ESPCOMP += -I$(ESPCOMP)/app_update/include
 INC_ESPCOMP += -I$(ESPCOMP)/pthread/include
 INC_ESPCOMP += -I$(ESPCOMP)/smartconfig_ack/include
 INC_ESPCOMP += -I$(ESPCOMP)/sdmmc/include
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+INC_ESPCOMP += -I$(ESPCOMP)/esp_common/include
+INC_ESPCOMP += -I$(ESPCOMP)/esp_eth/include
+INC_ESPCOMP += -I$(ESPCOMP)/esp_event/private_include
+INC_ESPCOMP += -I$(ESPCOMP)/esp_rom/include
+INC_ESPCOMP += -I$(ESPCOMP)/esp_wifi/include
+INC_ESPCOMP += -I$(ESPCOMP)/esp_wifi/esp32/include
+INC_ESPCOMP += -I$(ESPCOMP)/lwip/include/apps/sntp
+INC_ESPCOMP += -I$(ESPCOMP)/spi_flash/private_include
+INC_ESPCOMP += -I$(ESPCOMP)/wpa_supplicant/include/esp_supplicant
+INC_ESPCOMP += -I$(ESPCOMP)/xtensa/include
+INC_ESPCOMP += -I$(ESPCOMP)/xtensa/esp32/include
+else
+INC_ESPCOMP += -I$(ESPCOMP)/ethernet/include
+INC_ESPCOMP += -I$(ESPCOMP)/expat/expat/expat/lib
+INC_ESPCOMP += -I$(ESPCOMP)/expat/port/include
+INC_ESPCOMP += -I$(ESPCOMP)/json/include
+INC_ESPCOMP += -I$(ESPCOMP)/json/port/include
+INC_ESPCOMP += -I$(ESPCOMP)/micro-ecc/micro-ecc
+INC_ESPCOMP += -I$(ESPCOMP)/nghttp/port/include
+INC_ESPCOMP += -I$(ESPCOMP)/nghttp/nghttp2/lib/includes
+endif
+
 # these flags are common to C and C++ compilation
 CFLAGS_COMMON = -Os -ffunction-sections -fdata-sections -fstrict-volatile-bitfields \
 	-mlongcalls -nostdlib \
@@ -156,6 +182,10 @@ CFLAGS += -DIDF_VER=\"$(IDF_VER)\"
 CFLAGS += $(CFLAGS_MOD) $(CFLAGS_EXTRA)
 CFLAGS += -I$(BOARD_DIR)
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+CFLAGS += -DMICROPY_ESP_IDF_4=1
+endif
+
 # this is what ESPIDF uses for c++ compilation
 CXXFLAGS = -std=gnu++11 $(CFLAGS_COMMON) $(INC) $(INC_ESPCOMP)
 
@@ -164,6 +194,7 @@ LDFLAGS += --gc-sections -static -EL
 LDFLAGS += -u call_user_start_cpu0 -u uxTopUsedPriority -u ld_include_panic_highint_hdl
 LDFLAGS += -u __cxa_guard_dummy # so that implementation of static guards is taken from cxx_guards.o instead of libstdc++.a
 LDFLAGS += -L$(ESPCOMP)/esp32/ld
+LDFLAGS += -L$(ESPCOMP)/esp_rom/esp32/ld
 LDFLAGS += -T $(BUILD)/esp32_out.ld
 LDFLAGS += -T $(BUILD)/esp32.project.ld
 LDFLAGS += -T esp32.rom.ld
@@ -183,12 +214,19 @@ COPT += -Os -DNDEBUG
 #LDFLAGS += --gc-sections
 endif
 
-# Enable SPIRAM support if CONFIG_SPIRAM_SUPPORT=y in sdkconfig
-ifeq ($(CONFIG_SPIRAM_SUPPORT),y)
+# Enable SPIRAM support if CONFIG_ESP32_SPIRAM_SUPPORT=y in sdkconfig
+ifeq ($(CONFIG_ESP32_SPIRAM_SUPPORT),y)
 CFLAGS_COMMON += -mfix-esp32-psram-cache-issue
 LIBC_LIBM = $(ESPCOMP)/newlib/lib/libc-psram-workaround.a $(ESPCOMP)/newlib/lib/libm-psram-workaround.a
 else
+# Additional newlib symbols that can only be used with spiram disabled.
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+LDFLAGS += -T esp32.rom.newlib-funcs.ld
+LDFLAGS += -T esp32.rom.newlib-locale.ld
+LDFLAGS += -T esp32.rom.newlib-data.ld
+else
 LDFLAGS += -T esp32.rom.spiram_incompatible_fns.ld
+endif
 LIBC_LIBM = $(ESPCOMP)/newlib/lib/libc.a $(ESPCOMP)/newlib/lib/libm.a
 endif
 
@@ -283,7 +321,8 @@ $(SDKCONFIG_H): $(SDKCONFIG_COMBINED)
 		--env "IDF_TARGET=esp32" \
 		--env "IDF_CMAKE=n" \
 		--env "COMPONENT_KCONFIGS=$(ESPCOMP_KCONFIGS)" \
-		--env "COMPONENT_KCONFIGS_PROJBUILD=$(ESPCOMP_KCONFIGS_PROJBUILD)"
+		--env "COMPONENT_KCONFIGS_PROJBUILD=$(ESPCOMP_KCONFIGS_PROJBUILD)" \
+		--env "IDF_PATH=$(ESPIDF)"
 	$(Q)touch $@
 
 $(HEADER_BUILD)/qstrdefs.generated.h: $(SDKCONFIG_H) $(BOARD_DIR)/mpconfigboard.h
@@ -293,7 +332,9 @@ $(HEADER_BUILD)/qstrdefs.generated.h: $(SDKCONFIG_H) $(BOARD_DIR)/mpconfigboard.
 
 ESPIDF_BOOTLOADER_SUPPORT_O = $(patsubst %.c,%.o,\
 	$(filter-out $(ESPCOMP)/bootloader_support/src/bootloader_init.c,\
-		$(wildcard $(ESPCOMP)/bootloader_support/src/*.c)))
+		$(wildcard $(ESPCOMP)/bootloader_support/src/*.c) \
+		$(wildcard $(ESPCOMP)/bootloader_support/src/idf/*.c) \
+		))
 
 ESPIDF_DRIVER_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/driver/*.c))
 
@@ -315,22 +356,22 @@ ESPIDF_HEAP_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/heap/*.c))
 ESPIDF_SOC_O = $(patsubst %.c,%.o,\
 	$(wildcard $(ESPCOMP)/soc/esp32/*.c) \
 	$(wildcard $(ESPCOMP)/soc/src/*.c) \
+	$(wildcard $(ESPCOMP)/soc/src/hal/*.c) \
 	)
 
 ESPIDF_CXX_O = $(patsubst %.cpp,%.o,$(wildcard $(ESPCOMP)/cxx/*.cpp))
 
-ESPIDF_ETHERNET_O = $(patsubst %.c,%.o,\
-	$(wildcard $(ESPCOMP)/ethernet/*.c) \
-	$(wildcard $(ESPCOMP)/ethernet/eth_phy/*.c) \
-	)
-
 ESPIDF_PTHREAD_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/pthread/*.c))
 
 # Assembler .S files need only basic flags, and in particular should not have
 # -Os because that generates subtly different code.
 # We also need custom CFLAGS for .c files because FreeRTOS has headers with
 # generic names (eg queue.h) which can clash with other files in the port.
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+CFLAGS_ASM = -I$(BUILD) -I$(ESPCOMP)/esp32/include -I$(ESPCOMP)/soc/esp32/include -I$(ESPCOMP)/freertos/include/freertos -I. -I$(ESPCOMP)/xtensa/include -I$(ESPCOMP)/xtensa/esp32/include -I$(ESPCOMP)/esp_common/include
+else
 CFLAGS_ASM = -I$(BUILD) -I$(ESPCOMP)/esp32/include -I$(ESPCOMP)/soc/esp32/include -I$(ESPCOMP)/freertos/include/freertos -I.
+endif
 $(BUILD)/$(ESPCOMP)/freertos/portasm.o: CFLAGS = $(CFLAGS_ASM)
 $(BUILD)/$(ESPCOMP)/freertos/xtensa_context.o: CFLAGS = $(CFLAGS_ASM)
 $(BUILD)/$(ESPCOMP)/freertos/xtensa_intr_asm.o: CFLAGS = $(CFLAGS_ASM)
@@ -343,8 +384,6 @@ ESPIDF_FREERTOS_O = \
 
 ESPIDF_VFS_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/vfs/*.c))
 
-ESPIDF_JSON_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/json/cJSON/cJSON*.c))
-
 ESPIDF_LOG_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/log/*.c))
 
 ESPIDF_XTENSA_DEBUG_MODULE_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/xtensa-debug-module/*.c))
@@ -382,11 +421,16 @@ ESPIDF_LWIP_O = $(patsubst %.c,%.o,\
 ESPIDF_MBEDTLS_O = $(patsubst %.c,%.o,\
 	$(wildcard $(ESPCOMP)/mbedtls/mbedtls/library/*.c) \
 	$(wildcard $(ESPCOMP)/mbedtls/port/*.c) \
+	$(wildcard $(ESPCOMP)/mbedtls/port/esp32/*.c) \
 	)
 
 ESPIDF_MDNS_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/mdns/*.c))
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+$(BUILD)/$(ESPCOMP)/wpa_supplicant/%.o: CFLAGS += -DESP_SUPPLICANT -DIEEE8021X_EAPOL -DEAP_PEER_METHOD -DEAP_TLS -DEAP_TTLS -DEAP_PEAP -DEAP_MSCHAPv2 -DUSE_WPA2_TASK -DCONFIG_WPS2 -DCONFIG_WPS_PIN -DUSE_WPS_TASK -DESPRESSIF_USE -DESP32_WORKAROUND -DCONFIG_ECC -D__ets__ -Wno-strict-aliasing -I$(ESPCOMP)/wpa_supplicant/src -Wno-implicit-function-declaration
+else
 $(BUILD)/$(ESPCOMP)/wpa_supplicant/%.o: CFLAGS += -DEMBEDDED_SUPP -DIEEE8021X_EAPOL -DEAP_PEER_METHOD -DEAP_MSCHAPv2 -DEAP_TTLS -DEAP_TLS -DEAP_PEAP -DUSE_WPA2_TASK -DCONFIG_WPS2 -DCONFIG_WPS_PIN -DUSE_WPS_TASK -DESPRESSIF_USE -DESP32_WORKAROUND -DALLOW_EVEN_MOD -D__ets__ -Wno-strict-aliasing
+endif
 ESPIDF_WPA_SUPPLICANT_O = $(patsubst %.c,%.o,\
 	$(wildcard $(ESPCOMP)/wpa_supplicant/port/*.c) \
 	$(wildcard $(ESPCOMP)/wpa_supplicant/src/*/*.c) \
@@ -394,6 +438,29 @@ ESPIDF_WPA_SUPPLICANT_O = $(patsubst %.c,%.o,\
 
 ESPIDF_SDMMC_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/sdmmc/*.c))
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+ESPIDF_ESP_COMMON_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/esp_common/src/*.c))
+
+ESPIDF_ESP_EVENT_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/esp_event/*.c))
+
+ESPIDF_ESP_WIFI_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/esp_wifi/src/*.c))
+
+$(BUILD)/$(ESPCOMP)/esp_eth/src/esp_eth_mac_dm9051.o: CFLAGS += -fno-strict-aliasing
+ESPIDF_ESP_ETH_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/esp_eth/src/*.c))
+
+ESPIDF_XTENSA_O = $(patsubst %.c,%.o,\
+    $(wildcard $(ESPCOMP)/xtensa/*.c) \
+    $(wildcard $(ESPCOMP)/xtensa/esp32/*.c) \
+    )
+else
+ESPIDF_JSON_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/json/cJSON/cJSON*.c))
+
+ESPIDF_ETHERNET_O = $(patsubst %.c,%.o,\
+    $(wildcard $(ESPCOMP)/ethernet/*.c) \
+    $(wildcard $(ESPCOMP)/ethernet/eth_phy/*.c) \
+    )
+endif
+
 OBJ_ESPIDF =
 LIB_ESPIDF =
 BUILD_ESPIDF_LIB = $(BUILD)/esp-idf
@@ -414,7 +481,6 @@ $(eval $(call gen_espidf_lib_rule,esp_ringbuf,$(ESPIDF_ESP_RINGBUF_O)))
 $(eval $(call gen_espidf_lib_rule,heap,$(ESPIDF_HEAP_O)))
 $(eval $(call gen_espidf_lib_rule,soc,$(ESPIDF_SOC_O)))
 $(eval $(call gen_espidf_lib_rule,cxx,$(ESPIDF_CXX_O)))
-$(eval $(call gen_espidf_lib_rule,ethernet,$(ESPIDF_ETHERNET_O)))
 $(eval $(call gen_espidf_lib_rule,pthread,$(ESPIDF_PTHREAD_O)))
 $(eval $(call gen_espidf_lib_rule,freertos,$(ESPIDF_FREERTOS_O)))
 $(eval $(call gen_espidf_lib_rule,vfs,$(ESPIDF_VFS_O)))
@@ -435,6 +501,16 @@ $(eval $(call gen_espidf_lib_rule,mdns,$(ESPIDF_MDNS_O)))
 $(eval $(call gen_espidf_lib_rule,wpa_supplicant,$(ESPIDF_WPA_SUPPLICANT_O)))
 $(eval $(call gen_espidf_lib_rule,sdmmc,$(ESPIDF_SDMMC_O)))
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+$(eval $(call gen_espidf_lib_rule,esp_common,$(ESPIDF_ESP_COMMON_O)))
+$(eval $(call gen_espidf_lib_rule,esp_event,$(ESPIDF_ESP_EVENT_O)))
+$(eval $(call gen_espidf_lib_rule,esp_wifi,$(ESPIDF_ESP_WIFI_O)))
+$(eval $(call gen_espidf_lib_rule,esp_eth,$(ESPIDF_ESP_ETH_O)))
+$(eval $(call gen_espidf_lib_rule,xtensa,$(ESPIDF_XTENSA_O)))
+else
+$(eval $(call gen_espidf_lib_rule,ethernet,$(ESPIDF_ETHERNET_O)))
+endif
+
 # Create all destination build dirs before compiling IDF source
 OBJ_ESPIDF_DIRS = $(sort $(dir $(OBJ_ESPIDF))) $(BUILD_ESPIDF_LIB) $(addprefix $(BUILD_ESPIDF_LIB)/,$(LIB_ESPIDF))
 $(OBJ_ESPIDF): | $(OBJ_ESPIDF_DIRS)
@@ -451,6 +527,32 @@ LIB = $(foreach lib,$(LIB_ESPIDF),$(BUILD_ESPIDF_LIB)/$(lib)/lib$(lib).a)
 # ESP IDF ldgen
 
 LDGEN_FRAGMENTS = $(shell find $(ESPCOMP) -name "*.lf")
+
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+
+LDGEN_LIBRARIES=$(foreach lib,$(LIB_ESPIDF),$(BUILD_ESPIDF_LIB)/$(lib)/lib$(lib).a)
+
+$(BUILD_ESPIDF_LIB)/ldgen_libraries: $(LDGEN_LIBRARIES) $(ESPIDF)/make/ldgen.mk
+	printf "$(foreach library,$(LDGEN_LIBRARIES),$(library)\n)" > $(BUILD_ESPIDF_LIB)/ldgen_libraries
+
+$(BUILD)/esp32.project.ld: $(ESPCOMP)/esp32/ld/esp32.project.ld.in $(LDGEN_FRAGMENTS) $(SDKCONFIG_COMBINED) $(BUILD_ESPIDF_LIB)/ldgen_libraries
+	$(ECHO) "GEN $@"
+	$(Q)$(PYTHON) $(ESPIDF)/tools/ldgen/ldgen.py \
+		--input $< \
+		--output $@ \
+		--config $(SDKCONFIG_COMBINED) \
+		--kconfig $(ESPIDF)/Kconfig \
+		--fragments $(LDGEN_FRAGMENTS) \
+		--libraries-file $(BUILD_ESPIDF_LIB)/ldgen_libraries \
+		--env "IDF_TARGET=esp32" \
+		--env "IDF_CMAKE=n" \
+		--env "COMPONENT_KCONFIGS=$(ESPCOMP_KCONFIGS)" \
+		--env "COMPONENT_KCONFIGS_PROJBUILD=$(ESPCOMP_KCONFIGS_PROJBUILD)" \
+		--env "IDF_PATH=$(ESPIDF)" \
+		--objdump $(OBJDUMP)
+
+else
+
 LDGEN_SECTIONS_INFO = $(foreach lib,$(LIB_ESPIDF),$(BUILD_ESPIDF_LIB)/$(lib)/lib$(lib).a.sections_info)
 LDGEN_SECTION_INFOS = $(BUILD_ESPIDF_LIB)/ldgen.section_infos
 
@@ -477,7 +579,10 @@ $(BUILD)/esp32.project.ld: $(ESPCOMP)/esp32/ld/esp32.project.ld.in $(LDGEN_FRAGM
 		--env "IDF_TARGET=esp32" \
 		--env "IDF_CMAKE=n" \
 		--env "COMPONENT_KCONFIGS=$(ESPCOMP_KCONFIGS)" \
-		--env "COMPONENT_KCONFIGS_PROJBUILD=$(ESPCOMP_KCONFIGS_PROJBUILD)"
+		--env "COMPONENT_KCONFIGS_PROJBUILD=$(ESPCOMP_KCONFIGS_PROJBUILD)" \
+		--env "IDF_PATH=$(ESPIDF)"
+
+endif
 
 ################################################################################
 # Main targets
@@ -513,8 +618,13 @@ APP_LD_ARGS += --start-group
 APP_LD_ARGS += -L$(dir $(LIBGCC_FILE_NAME)) -lgcc
 APP_LD_ARGS += -L$(dir $(LIBSTDCXX_FILE_NAME)) -lstdc++
 APP_LD_ARGS += $(LIBC_LIBM)
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+APP_LD_ARGS += -L$(ESPCOMP)/xtensa/esp32 -lhal
+APP_LD_ARGS += -L$(ESPCOMP)/esp_wifi/lib_esp32 -lcore -lmesh -lnet80211 -lphy -lrtc -lpp -lsmartconfig -lcoexist
+else
 APP_LD_ARGS += $(ESPCOMP)/esp32/libhal.a
 APP_LD_ARGS += -L$(ESPCOMP)/esp32/lib -lcore -lmesh -lnet80211 -lphy -lrtc -lpp -lwpa -lsmartconfig -lcoexist -lwps -lwpa2
+endif
 APP_LD_ARGS += $(OBJ)
 APP_LD_ARGS += $(LIB)
 APP_LD_ARGS += --end-group
@@ -553,7 +663,14 @@ $(BUILD)/%.o: %.cpp
 BOOTLOADER_LIB_DIR = $(BUILD)/bootloader
 BOOTLOADER_LIB_ALL =
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+$(BUILD)/bootloader/$(ESPCOMP)/%.o: CFLAGS += -DBOOTLOADER_BUILD=1 -I$(ESPCOMP)/bootloader_support/include_priv -I$(ESPCOMP)/bootloader_support/include -I$(ESPCOMP)/efuse/include -I$(ESPCOMP)/esp_rom/include -Wno-error=format \
+	-I$(ESPCOMP)/esp_common/include \
+	-I$(ESPCOMP)/xtensa/include \
+	-I$(ESPCOMP)/xtensa/esp32/include
+else
 $(BUILD)/bootloader/$(ESPCOMP)/%.o: CFLAGS += -DBOOTLOADER_BUILD=1 -I$(ESPCOMP)/bootloader_support/include_priv -I$(ESPCOMP)/bootloader_support/include -I$(ESPCOMP)/micro-ecc/micro-ecc -I$(ESPCOMP)/efuse/include -I$(ESPCOMP)/esp32 -Wno-error=format
+endif
 
 # libbootloader_support.a
 BOOTLOADER_LIB_ALL += bootloader_support
@@ -563,15 +680,27 @@ BOOTLOADER_LIB_BOOTLOADER_SUPPORT_OBJ = $(addprefix $(BUILD)/bootloader/$(ESPCOM
 	bootloader_support/src/bootloader_flash.o \
 	bootloader_support/src/bootloader_init.o \
 	bootloader_support/src/bootloader_random.o \
-	bootloader_support/src/bootloader_sha.o \
 	bootloader_support/src/bootloader_utility.o \
 	bootloader_support/src/flash_qio_mode.o \
-	bootloader_support/src/secure_boot_signatures.o \
-	bootloader_support/src/secure_boot.o \
 	bootloader_support/src/esp_image_format.o \
 	bootloader_support/src/flash_encrypt.o \
 	bootloader_support/src/flash_partitions.o \
 	)
+
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+BOOTLOADER_LIB_BOOTLOADER_SUPPORT_OBJ += $(addprefix $(BUILD)/bootloader/$(ESPCOMP)/,\
+	bootloader_support/src/esp32/bootloader_sha.o \
+	bootloader_support/src/bootloader_flash_config.o \
+	bootloader_support/src/esp32/secure_boot.o \
+	)
+else
+BOOTLOADER_LIB_BOOTLOADER_SUPPORT_OBJ += $(addprefix $(BUILD)/bootloader/$(ESPCOMP)/,\
+	bootloader_support/src/bootloader_sha.o \
+	bootloader_support/src/secure_boot_signatures.o \
+	bootloader_support/src/secure_boot.o \
+	)
+endif
+
 $(BOOTLOADER_LIB_DIR)/libbootloader_support.a: $(BOOTLOADER_LIB_BOOTLOADER_SUPPORT_OBJ)
 	$(ECHO) "AR $@"
 	$(Q)$(AR) cr $@ $^
@@ -594,6 +723,7 @@ $(BOOTLOADER_LIB_DIR)/libspi_flash.a: $(BOOTLOADER_LIB_SPI_FLASH_OBJ)
 	$(ECHO) "AR $@"
 	$(Q)$(AR) cr $@ $^
 
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V3))
 # libmicro-ecc.a
 BOOTLOADER_LIB_ALL += micro-ecc
 BOOTLOADER_LIB_MICRO_ECC_OBJ = $(addprefix $(BUILD)/bootloader/$(ESPCOMP)/,\
@@ -602,6 +732,7 @@ BOOTLOADER_LIB_MICRO_ECC_OBJ = $(addprefix $(BUILD)/bootloader/$(ESPCOMP)/,\
 $(BOOTLOADER_LIB_DIR)/libmicro-ecc.a: $(BOOTLOADER_LIB_MICRO_ECC_OBJ)
 	$(ECHO) "AR $@"
 	$(Q)$(AR) cr $@ $^
+endif
 
 # libsoc.a
 $(BUILD)/bootloader/$(ESPCOMP)/soc/esp32/rtc_clk.o: CFLAGS += -fno-jump-tables -fno-tree-switch-conversion
@@ -651,7 +782,11 @@ BOOTLOADER_LIBS =
 BOOTLOADER_LIBS += -Wl,--start-group
 BOOTLOADER_LIBS += $(BOOTLOADER_OBJ)
 BOOTLOADER_LIBS += -L$(BUILD)/bootloader $(addprefix -l,$(BOOTLOADER_LIB_ALL))
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+BOOTLOADER_LIBS += -L$(ESPCOMP)/esp_wifi/lib_esp32 -lrtc
+else
 BOOTLOADER_LIBS += -L$(ESPCOMP)/esp32/lib -lrtc
+endif
 BOOTLOADER_LIBS += -L$(dir $(LIBGCC_FILE_NAME)) -lgcc
 BOOTLOADER_LIBS += -Wl,--end-group
 
@@ -666,8 +801,13 @@ BOOTLOADER_LDFLAGS += -Wl,-EL
 BOOTLOADER_LDFLAGS += -Wl,-Map=$(@:.elf=.map) -Wl,--cref
 BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/bootloader/subproject/main/esp32.bootloader.ld
 BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/bootloader/subproject/main/esp32.bootloader.rom.ld
+ifeq ($(ESPIDF_CURHASH),$(ESPIDF_SUPHASH_V4))
+BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/esp_rom/esp32/ld/esp32.rom.ld
+BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/esp_rom/esp32/ld/esp32.rom.newlib-funcs.ld
+else
 BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/esp32/ld/esp32.rom.ld
 BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/esp32/ld/esp32.rom.spiram_incompatible_fns.ld
+endif
 BOOTLOADER_LDFLAGS += -T $(ESPCOMP)/esp32/ld/esp32.peripherals.ld
 
 BOOTLOADER_OBJ_DIRS = $(sort $(dir $(BOOTLOADER_OBJ_ALL)))
diff --git a/ports/esp32/boards/TINYPICO/sdkconfig.board b/ports/esp32/boards/TINYPICO/sdkconfig.board
index ea4fc9b5c..dc2c23f67 100644
--- a/ports/esp32/boards/TINYPICO/sdkconfig.board
+++ b/ports/esp32/boards/TINYPICO/sdkconfig.board
@@ -1,3 +1,4 @@
 CONFIG_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
 CONFIG_SPIRAM_SPEED_80M=y
+CONFIG_ESP32_REV_MIN_1=y
diff --git a/ports/esp32/boards/sdkconfig.base b/ports/esp32/boards/sdkconfig.base
index 7bd731a66..d44a97e13 100644
--- a/ports/esp32/boards/sdkconfig.base
+++ b/ports/esp32/boards/sdkconfig.base
@@ -8,7 +8,7 @@ CONFIG_APP_EXCLUDE_PROJECT_VER_VAR=y
 CONFIG_APP_EXCLUDE_PROJECT_NAME_VAR=y
 
 # Bootloader config
-CONFIG_LOG_BOOTLOADER_LEVEL_WARN=y
+CONFIG_BOOTLOADER_LOG_LEVEL_WARN=y
 
 # ESP32-specific
 CONFIG_ESP32_DEFAULT_CPU_FREQ_240=y
@@ -21,10 +21,15 @@ CONFIG_PM_ENABLE=y
 
 # FreeRTOS
 CONFIG_FREERTOS_THREAD_LOCAL_STORAGE_POINTERS=2
-CONFIG_SUPPORT_STATIC_ALLOCATION=y
-CONFIG_ENABLE_STATIC_TASK_CLEAN_UP_HOOK=y
+CONFIG_FREERTOS_SUPPORT_STATIC_ALLOCATION=y
+CONFIG_FREERTOS_ENABLE_STATIC_TASK_CLEAN_UP=y
 
 # UDP
 CONFIG_PPP_SUPPORT=y
 CONFIG_PPP_PAP_SUPPORT=y
 CONFIG_PPP_CHAP_SUPPORT=y
+
+# v3.3-only (renamed in 4.0)
+CONFIG_LOG_BOOTLOADER_LEVEL_WARN=y
+CONFIG_SUPPORT_STATIC_ALLOCATION=y
+CONFIG_ENABLE_STATIC_TASK_CLEAN_UP_HOOK=y
diff --git a/ports/esp32/boards/sdkconfig.spiram b/ports/esp32/boards/sdkconfig.spiram
index 53950e587..db1a83af8 100644
--- a/ports/esp32/boards/sdkconfig.spiram
+++ b/ports/esp32/boards/sdkconfig.spiram
@@ -1,5 +1,9 @@
 # MicroPython on ESP32, ESP IDF configuration with SPIRAM support
 
-CONFIG_SPIRAM_SUPPORT=y
+CONFIG_ESP32_SPIRAM_SUPPORT=y
+CONFIG_SPIRAM_CACHE_WORKAROUND=y
 CONFIG_SPIRAM_IGNORE_NOTFOUND=y
 CONFIG_SPIRAM_USE_MEMMAP=y
+
+# v3.3-only (renamed in 4.0)
+CONFIG_SPIRAM_SUPPORT=y
diff --git a/ports/esp32/esp32_ulp.c b/ports/esp32/esp32_ulp.c
index 3772639f4..bf11de330 100644
--- a/ports/esp32/esp32_ulp.c
+++ b/ports/esp32/esp32_ulp.c
@@ -85,7 +85,11 @@ STATIC const mp_rom_map_elem_t esp32_ulp_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_set_wakeup_period), MP_ROM_PTR(&esp32_ulp_set_wakeup_period_obj) },
     { MP_ROM_QSTR(MP_QSTR_load_binary), MP_ROM_PTR(&esp32_ulp_load_binary_obj) },
     { MP_ROM_QSTR(MP_QSTR_run), MP_ROM_PTR(&esp32_ulp_run_obj) },
+    #if !MICROPY_ESP_IDF_4
     { MP_ROM_QSTR(MP_QSTR_RESERVE_MEM), MP_ROM_INT(CONFIG_ULP_COPROC_RESERVE_MEM) },
+    #else
+    { MP_ROM_QSTR(MP_QSTR_RESERVE_MEM), MP_ROM_INT(CONFIG_ESP32_ULP_COPROC_RESERVE_MEM) },
+    #endif
 };
 STATIC MP_DEFINE_CONST_DICT(esp32_ulp_locals_dict, esp32_ulp_locals_dict_table);
 
diff --git a/ports/esp32/main.c b/ports/esp32/main.c
index c8dde337c..4d25cf0b3 100644
--- a/ports/esp32/main.c
+++ b/ports/esp32/main.c
@@ -37,7 +37,11 @@
 #include "esp_task.h"
 #include "soc/cpu.h"
 #include "esp_log.h"
+#if MICROPY_ESP_IDF_4
+#include "esp32/spiram.h"
+#else
 #include "esp_spiram.h"
+#endif
 
 #include "py/stackctrl.h"
 #include "py/nlr.h"
@@ -70,7 +74,7 @@ void mp_task(void *pvParameter) {
     #endif
     uart_init();
 
-    #if CONFIG_SPIRAM_SUPPORT
+    #if CONFIG_ESP32_SPIRAM_SUPPORT
     // Try to use the entire external SPIRAM directly for the heap
     size_t mp_task_heap_size;
     void *mp_task_heap = (void*)0x3f800000;
@@ -150,7 +154,11 @@ soft_reset:
 }
 
 void app_main(void) {
-    nvs_flash_init();
+    esp_err_t ret = nvs_flash_init();
+    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        nvs_flash_erase();
+        nvs_flash_init();
+    }
     xTaskCreatePinnedToCore(mp_task, "mp_task", MP_TASK_STACK_LEN, NULL, MP_TASK_PRIORITY, &mp_main_task_handle, MP_TASK_COREID);
 }
 
diff --git a/ports/esp32/modesp.c b/ports/esp32/modesp.c
index e614f77a6..9584b789d 100644
--- a/ports/esp32/modesp.c
+++ b/ports/esp32/modesp.c
@@ -29,7 +29,9 @@
 
 #include <stdio.h>
 
+#if !MICROPY_ESP_IDF_4
 #include "rom/gpio.h"
+#endif
 #include "esp_log.h"
 #include "esp_spi_flash.h"
 
diff --git a/ports/esp32/modmachine.c b/ports/esp32/modmachine.c
index fb864947d..0c803d096 100644
--- a/ports/esp32/modmachine.c
+++ b/ports/esp32/modmachine.c
@@ -32,9 +32,15 @@
 
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
+#if MICROPY_ESP_IDF_4
+#include "esp32/rom/rtc.h"
+#include "esp32/clk.h"
+#include "esp_sleep.h"
+#else
 #include "rom/ets_sys.h"
 #include "rom/rtc.h"
 #include "esp_clk.h"
+#endif
 #include "esp_pm.h"
 #include "driver/touch_pad.h"
 
diff --git a/ports/esp32/modnetwork.c b/ports/esp32/modnetwork.c
index 45ea5139c..012dc5bce 100644
--- a/ports/esp32/modnetwork.c
+++ b/ports/esp32/modnetwork.c
@@ -43,20 +43,23 @@
 #include "netutils.h"
 #include "esp_eth.h"
 #include "esp_wifi.h"
-#include "esp_wifi_types.h"
 #include "esp_log.h"
-#include "esp_event_loop.h"
 #include "lwip/dns.h"
 #include "tcpip_adapter.h"
 #include "mdns.h"
 
+#if !MICROPY_ESP_IDF_4
+#include "esp_wifi_types.h"
+#include "esp_event_loop.h"
+#endif
+
 #include "modnetwork.h"
 
 #define MODNETWORK_INCLUDE_CONSTANTS (1)
 
 NORETURN void _esp_exceptions(esp_err_t e) {
    switch (e) {
-      case ESP_ERR_WIFI_NOT_INIT: 
+      case ESP_ERR_WIFI_NOT_INIT:
         mp_raise_msg(&mp_type_OSError, "Wifi Not Initialized");
       case ESP_ERR_WIFI_NOT_STARTED:
         mp_raise_msg(&mp_type_OSError, "Wifi Not Started");
@@ -93,7 +96,7 @@ NORETURN void _esp_exceptions(esp_err_t e) {
       case ESP_ERR_TCPIP_ADAPTER_DHCPC_START_FAILED:
         mp_raise_msg(&mp_type_OSError, "TCP/IP DHCP Client Start Failed");
       case ESP_ERR_TCPIP_ADAPTER_NO_MEM:
-        mp_raise_OSError(MP_ENOMEM); 
+        mp_raise_OSError(MP_ENOMEM);
       default:
         nlr_raise(mp_obj_new_exception_msg_varg(
           &mp_type_RuntimeError, "Wifi Unknown Error 0x%04x", e
@@ -650,9 +653,12 @@ STATIC mp_obj_t esp_config(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs
                   ESP_EXCEPTIONS(esp_wifi_get_mac(self->if_id, mac));
                   return mp_obj_new_bytes(mac, sizeof(mac));
 
+              #if !MICROPY_ESP_IDF_4
               case ESP_IF_ETH:
                   esp_eth_get_mac(mac);
                   return mp_obj_new_bytes(mac, sizeof(mac));
+              #endif
+
               default:
                   goto unknown;
             }
@@ -734,8 +740,10 @@ STATIC const mp_rom_map_elem_t mp_module_network_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_network) },
     { MP_ROM_QSTR(MP_QSTR___init__), MP_ROM_PTR(&esp_initialize_obj) },
     { MP_ROM_QSTR(MP_QSTR_WLAN), MP_ROM_PTR(&get_wlan_obj) },
+    #if !MICROPY_ESP_IDF_4
     { MP_ROM_QSTR(MP_QSTR_LAN), MP_ROM_PTR(&get_lan_obj) },
     { MP_ROM_QSTR(MP_QSTR_PPP), MP_ROM_PTR(&ppp_make_new_obj) },
+    #endif
     { MP_ROM_QSTR(MP_QSTR_phy_mode), MP_ROM_PTR(&esp_phy_mode_obj) },
 
 #if MODNETWORK_INCLUDE_CONSTANTS
@@ -757,12 +765,14 @@ STATIC const mp_rom_map_elem_t mp_module_network_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_PHY_TLK110), MP_ROM_INT(PHY_TLK110) },
 
     // ETH Clock modes from ESP-IDF
+    #if !MICROPY_ESP_IDF_4
     { MP_ROM_QSTR(MP_QSTR_ETH_CLOCK_GPIO0_IN), MP_ROM_INT(ETH_CLOCK_GPIO0_IN) },
     // Disabled at Aug 22nd 2018, reenabled Jan 28th 2019 in ESP-IDF
     // Because we use older SDK, it's currently disabled
     //{ MP_ROM_QSTR(MP_QSTR_ETH_CLOCK_GPIO0_OUT), MP_ROM_INT(ETH_CLOCK_GPIO0_OUT) },
     { MP_ROM_QSTR(MP_QSTR_ETH_CLOCK_GPIO16_OUT), MP_ROM_INT(ETH_CLOCK_GPIO16_OUT) },
     { MP_ROM_QSTR(MP_QSTR_ETH_CLOCK_GPIO17_OUT), MP_ROM_INT(ETH_CLOCK_GPIO17_OUT) },
+    #endif
 
     { MP_ROM_QSTR(MP_QSTR_STAT_IDLE), MP_ROM_INT(STAT_IDLE)},
     { MP_ROM_QSTR(MP_QSTR_STAT_CONNECTING), MP_ROM_INT(STAT_CONNECTING)},
diff --git a/ports/esp32/modsocket.c b/ports/esp32/modsocket.c
index a6f29718d..e11af60e2 100644
--- a/ports/esp32/modsocket.c
+++ b/ports/esp32/modsocket.c
@@ -56,6 +56,18 @@
 #include "lwip/igmp.h"
 #include "esp_log.h"
 
+#if !MICROPY_ESP_IDF_4
+#define lwip_bind lwip_bind_r
+#define lwip_listen lwip_listen_r
+#define lwip_accept lwip_accept_r
+#define lwip_setsockopt lwip_setsockopt_r
+#define lwip_fnctl lwip_fnctl_r
+#define lwip_recvfrom lwip_recvfrom_r
+#define lwip_write lwip_write_r
+#define lwip_sendto lwip_sendto_r
+#define lwip_close lwip_close_r
+#endif
+
 #define SOCKET_POLL_US (100000)
 #define MDNS_QUERY_TIMEOUT_MS (5000)
 #define MDNS_LOCAL_SUFFIX ".local"
@@ -277,17 +289,17 @@ STATIC mp_obj_t socket_bind(const mp_obj_t arg0, const mp_obj_t arg1) {
     socket_obj_t *self = MP_OBJ_TO_PTR(arg0);
     struct addrinfo *res;
     _socket_getaddrinfo(arg1, &res);
-    int r = lwip_bind_r(self->fd, res->ai_addr, res->ai_addrlen);
+    int r = lwip_bind(self->fd, res->ai_addr, res->ai_addrlen);
     lwip_freeaddrinfo(res);
     if (r < 0) exception_from_errno(errno);
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(socket_bind_obj, socket_bind);
-    
+
 STATIC mp_obj_t socket_listen(const mp_obj_t arg0, const mp_obj_t arg1) {
     socket_obj_t *self = MP_OBJ_TO_PTR(arg0);
     int backlog = mp_obj_get_int(arg1);
-    int r = lwip_listen_r(self->fd, backlog);
+    int r = lwip_listen(self->fd, backlog);
     if (r < 0) exception_from_errno(errno);
     return mp_const_none;
 }
@@ -302,7 +314,7 @@ STATIC mp_obj_t socket_accept(const mp_obj_t arg0) {
     int new_fd = -1;
     for (int i=0; i<=self->retries; i++) {
         MP_THREAD_GIL_EXIT();
-        new_fd = lwip_accept_r(self->fd, &addr, &addr_len);
+        new_fd = lwip_accept(self->fd, &addr, &addr_len);
         MP_THREAD_GIL_ENTER();
         if (new_fd >= 0) break;
         if (errno != EAGAIN) exception_from_errno(errno);
@@ -342,7 +354,7 @@ STATIC mp_obj_t socket_connect(const mp_obj_t arg0, const mp_obj_t arg1) {
     struct addrinfo *res;
     _socket_getaddrinfo(arg1, &res);
     MP_THREAD_GIL_EXIT();
-    int r = lwip_connect_r(self->fd, res->ai_addr, res->ai_addrlen);
+    int r = lwip_connect(self->fd, res->ai_addr, res->ai_addrlen);
     MP_THREAD_GIL_ENTER();
     lwip_freeaddrinfo(res);
     if (r != 0) {
@@ -363,7 +375,7 @@ STATIC mp_obj_t socket_setsockopt(size_t n_args, const mp_obj_t *args) {
         // level: SOL_SOCKET
         case SO_REUSEADDR: {
             int val = mp_obj_get_int(args[3]);
-            int ret = lwip_setsockopt_r(self->fd, SOL_SOCKET, opt, &val, sizeof(int));
+            int ret = lwip_setsockopt(self->fd, SOL_SOCKET, opt, &val, sizeof(int));
             if (ret != 0) {
                 exception_from_errno(errno);
             }
@@ -424,9 +436,9 @@ void _socket_settimeout(socket_obj_t *sock, uint64_t timeout_ms) {
         .tv_sec = 0,
         .tv_usec = timeout_ms ? SOCKET_POLL_US : 0
     };
-    lwip_setsockopt_r(sock->fd, SOL_SOCKET, SO_SNDTIMEO, (const void *)&timeout, sizeof(timeout));
-    lwip_setsockopt_r(sock->fd, SOL_SOCKET, SO_RCVTIMEO, (const void *)&timeout, sizeof(timeout));
-    lwip_fcntl_r(sock->fd, F_SETFL, timeout_ms ? 0 : O_NONBLOCK);
+    lwip_setsockopt(sock->fd, SOL_SOCKET, SO_SNDTIMEO, (const void *)&timeout, sizeof(timeout));
+    lwip_setsockopt(sock->fd, SOL_SOCKET, SO_RCVTIMEO, (const void *)&timeout, sizeof(timeout));
+    lwip_fcntl(sock->fd, F_SETFL, timeout_ms ? 0 : O_NONBLOCK);
 }
 
 STATIC mp_obj_t socket_settimeout(const mp_obj_t arg0, const mp_obj_t arg1) {
@@ -459,7 +471,7 @@ STATIC mp_uint_t _socket_read_data(mp_obj_t self_in, void *buf, size_t size,
     socket_obj_t *sock = MP_OBJ_TO_PTR(self_in);
 
     // If the peer closed the connection then the lwIP socket API will only return "0" once
-    // from lwip_recvfrom_r and then block on subsequent calls.  To emulate POSIX behaviour,
+    // from lwip_recvfrom and then block on subsequent calls.  To emulate POSIX behaviour,
     // which continues to return "0" for each call on a closed socket, we set a flag when
     // the peer closed the socket.
     if (sock->peer_closed) {
@@ -482,7 +494,7 @@ STATIC mp_uint_t _socket_read_data(mp_obj_t self_in, void *buf, size_t size,
         if (release_gil) {
             MP_THREAD_GIL_EXIT();
         }
-        int r = lwip_recvfrom_r(sock->fd, buf, size, 0, from, from_len);
+        int r = lwip_recvfrom(sock->fd, buf, size, 0, from, from_len);
         if (release_gil) {
             MP_THREAD_GIL_ENTER();
         }
@@ -543,13 +555,13 @@ int _socket_send(socket_obj_t *sock, const char *data, size_t datalen) {
     int sentlen = 0;
     for (int i=0; i<=sock->retries && sentlen < datalen; i++) {
         MP_THREAD_GIL_EXIT();
-        int r = lwip_write_r(sock->fd, data+sentlen, datalen-sentlen);
+        int r = lwip_write(sock->fd, data+sentlen, datalen-sentlen);
         MP_THREAD_GIL_ENTER();
         if (r < 0 && errno != EWOULDBLOCK) exception_from_errno(errno);
         if (r > 0) sentlen += r;
         check_for_exceptions();
     }
-    if (sentlen == 0) mp_raise_OSError(MP_ETIMEDOUT); 
+    if (sentlen == 0) mp_raise_OSError(MP_ETIMEDOUT);
     return sentlen;
 }
 
@@ -590,7 +602,7 @@ STATIC mp_obj_t socket_sendto(mp_obj_t self_in, mp_obj_t data_in, mp_obj_t addr_
     // send the data
     for (int i=0; i<=self->retries; i++) {
         MP_THREAD_GIL_EXIT();
-        int ret = lwip_sendto_r(self->fd, bufinfo.buf, bufinfo.len, 0, (struct sockaddr*)&to, sizeof(to));
+        int ret = lwip_sendto(self->fd, bufinfo.buf, bufinfo.len, 0, (struct sockaddr*)&to, sizeof(to));
         MP_THREAD_GIL_ENTER();
         if (ret > 0) return mp_obj_new_int_from_uint(ret);
         if (ret == -1 && errno != EWOULDBLOCK) {
@@ -598,7 +610,7 @@ STATIC mp_obj_t socket_sendto(mp_obj_t self_in, mp_obj_t data_in, mp_obj_t addr_
         }
         check_for_exceptions();
     }
-    mp_raise_OSError(MP_ETIMEDOUT); 
+    mp_raise_OSError(MP_ETIMEDOUT);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_3(socket_sendto_obj, socket_sendto);
 
@@ -622,7 +634,7 @@ STATIC mp_uint_t socket_stream_write(mp_obj_t self_in, const void *buf, mp_uint_
     socket_obj_t *sock = self_in;
     for (int i=0; i<=sock->retries; i++) {
         MP_THREAD_GIL_EXIT();
-        int r = lwip_write_r(sock->fd, buf, size);
+        int r = lwip_write(sock->fd, buf, size);
         MP_THREAD_GIL_ENTER();
         if (r > 0) return r;
         if (r < 0 && errno != EWOULDBLOCK) { *errcode = errno; return MP_STREAM_ERROR; }
@@ -663,7 +675,7 @@ STATIC mp_uint_t socket_stream_ioctl(mp_obj_t self_in, mp_uint_t request, uintpt
                 socket->events_callback = MP_OBJ_NULL;
             }
             #endif
-            int ret = lwip_close_r(socket->fd);
+            int ret = lwip_close(socket->fd);
             if (ret != 0) {
                 *errcode = errno;
                 return MP_STREAM_ERROR;
@@ -731,7 +743,7 @@ STATIC mp_obj_t esp_socket_getaddrinfo(size_t n_args, const mp_obj_t *args) {
             mp_obj_new_str(resi->ai_canonname, strlen(resi->ai_canonname)),
             mp_const_none
         };
-        
+
         if (resi->ai_family == AF_INET) {
             struct sockaddr_in *addr = (struct sockaddr_in *)resi->ai_addr;
             // This looks odd, but it's really just a u32_t
diff --git a/ports/esp32/mpconfigport.h b/ports/esp32/mpconfigport.h
index cba319245..1c0d8700f 100644
--- a/ports/esp32/mpconfigport.h
+++ b/ports/esp32/mpconfigport.h
@@ -6,7 +6,10 @@
 
 #include <stdint.h>
 #include <alloca.h>
+
+#if !MICROPY_ESP_IDF_4
 #include "rom/ets_sys.h"
+#endif
 
 // object representation and NLR handling
 #define MICROPY_OBJ_REPR                    (MICROPY_OBJ_REPR_A)
diff --git a/ports/esp32/mphalport.c b/ports/esp32/mphalport.c
index 0d1ea74d6..305e87593 100644
--- a/ports/esp32/mphalport.c
+++ b/ports/esp32/mphalport.c
@@ -31,7 +31,12 @@
 
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
+
+#if MICROPY_ESP_IDF_4
+#include "esp32/rom/uart.h"
+#else
 #include "rom/uart.h"
+#endif
 
 #include "py/obj.h"
 #include "py/stream.h"
diff --git a/ports/esp32/mpthreadport.c b/ports/esp32/mpthreadport.c
index 9557d4071..1c0d889e9 100644
--- a/ports/esp32/mpthreadport.c
+++ b/ports/esp32/mpthreadport.c
@@ -33,6 +33,9 @@
 #include "mpthreadport.h"
 
 #include "esp_task.h"
+#if !MICROPY_ESP_IDF_4
+#include "freertos/semphr.h"
+#endif
 
 #if MICROPY_PY_THREAD
 
diff --git a/ports/esp32/network_lan.c b/ports/esp32/network_lan.c
index 100894b2e..291040797 100644
--- a/ports/esp32/network_lan.c
+++ b/ports/esp32/network_lan.c
@@ -26,6 +26,7 @@
  * THE SOFTWARE.
  */
 
+#if !MICROPY_ESP_IDF_4
 #include "py/runtime.h"
 #include "py/mphal.h"
 
@@ -216,3 +217,5 @@ const mp_obj_type_t lan_if_type = {
     .name = MP_QSTR_LAN,
     .locals_dict = (mp_obj_dict_t*)&lan_if_locals_dict,
 };
+
+#endif // !MICROPY_ESP_IDF_4
diff --git a/ports/esp32/network_ppp.c b/ports/esp32/network_ppp.c
index 1a14c09bf..d868450fd 100644
--- a/ports/esp32/network_ppp.c
+++ b/ports/esp32/network_ppp.c
@@ -26,6 +26,7 @@
  * THE SOFTWARE.
  */
 
+#if !MICROPY_ESP_IDF_4
 #include "py/runtime.h"
 #include "py/mphal.h"
 #include "py/objtype.h"
@@ -282,3 +283,5 @@ const mp_obj_type_t ppp_if_type = {
     .name = MP_QSTR_PPP,
     .locals_dict = (mp_obj_dict_t*)&ppp_if_locals_dict,
 };
+
+#endif // !MICROPY_ESP_IDF_4