diff --git a/cpu/esp8266/Makefile b/cpu/esp8266/Makefile
index bc70b8de96..ebb63f918f 100644
--- a/cpu/esp8266/Makefile
+++ b/cpu/esp8266/Makefile
@@ -12,6 +12,6 @@ ifneq (, $(filter esp_wifi, $(USEMODULE)))
     DIRS += esp-wifi
 endif
 
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/esp8266/include/internal
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/esp8266/include/internal
 
 include $(RIOTBASE)/Makefile.base
diff --git a/cpu/esp8266/Makefile.include b/cpu/esp8266/Makefile.include
index 077b71a75c..bf33aa1f36 100644
--- a/cpu/esp8266/Makefile.include
+++ b/cpu/esp8266/Makefile.include
@@ -1,9 +1,9 @@
 # check some environment variables first
 
-ifndef ESP8266_SDK_DIR
-    $(info ESP8266_SDK_DIR should be defined as /path/to/sdk directory)
-    $(info ESP8266_SDK_DIR is set by default to /opt/esp/esp-open-sdk/sdk)
-    export ESP8266_SDK_DIR=/opt/esp/ESP8266-RTOS-SDK
+ifndef ESP8266_RTOS_SDK_DIR
+    $(info ESP8266_RTOS_SDK_DIR should be defined as /path/to/sdk directory)
+    $(info ESP8266_RTOS_SDK_DIR is set by default to /opt/esp/ESP8266-RTOS-SDK)
+    export ESP8266_RTOS_SDK_DIR=/opt/esp/ESP8266-RTOS-SDK
 endif
 
 # Options to control the compilation
@@ -86,14 +86,14 @@ INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/esp8266/include
 INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/esp8266/include/esp8266
 INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/heap/include
 INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/log/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/bootloader_support/include/
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/esp8266/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/esp8266/include/esp8266
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/heap/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/heap/port/esp8266/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/nvs_flash/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/spi_flash/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/bootloader_support/include/
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/esp8266/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/esp8266/include/esp8266
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/heap/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/heap/port/esp8266/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/nvs_flash/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/spi_flash/include
 
 CFLAGS  += -D__ESP_FILE__=__FILE__ -DDEVELHELP
 CFLAGS  += -Wno-unused-parameter -Wformat=0
@@ -172,7 +172,7 @@ FLASH_FREQ = 26m   # FIX configuration, DO NOT CHANGE
 FLASH_SIZE ?= 1MB
 FLASHDEPS  += preflash
 
-PREFLASHER ?= $(ESP8266_SDK_DIR)/components/esptool_py/esptool/esptool.py
+PREFLASHER ?= $(ESP8266_RTOS_SDK_DIR)/components/esptool_py/esptool/esptool.py
 PREFFLAGS  = --chip esp8266 elf2image
 PREFFLAGS += --flash_mode $(FLASH_MODE) --flash_size $(FLASH_SIZE)
 PREFFLAGS += --flash_freq $(FLASH_FREQ) --version 3
diff --git a/cpu/esp8266/doc.txt b/cpu/esp8266/doc.txt
index 63403459d1..293994024f 100644
--- a/cpu/esp8266/doc.txt
+++ b/cpu/esp8266/doc.txt
@@ -334,10 +334,10 @@ necessary changes.
 SDK does not need to be compiled in any way.
 
 To use the installed ESP8266 RTOS SDK, set the environment variable
-`ESP8266_SDK_DIR`.
+`ESP8266_RTOS_SDK_DIR`.
 
 ```
-export ESP8266_SDK_DIR=$HOME/esp/ESP8266_RTOS_SDK
+export ESP8266_RTOS_SDK_DIR=$HOME/esp/ESP8266_RTOS_SDK
 ```
 
 
@@ -393,7 +393,7 @@ correctly to
 
 ```
 export PATH=/path/to/esp/esptool-esp8266-rtos-sdk-v3:/path/to/esp/xtensa-lx106-elf/bin:$PATH
-export ESP8266_SDK_DIR=/path/to/esp/ESP8266_RTOS_SDK
+export ESP8266_RTOS_SDK_DIR=/path/to/esp/ESP8266_RTOS_SDK
 ```
 
 ## <a name="esp8266_compile_options"> Compile Options </a> &nbsp;[[TOC](#esp8266_toc)]
diff --git a/cpu/esp8266/esp-wifi/Makefile b/cpu/esp8266/esp-wifi/Makefile
index 146f3bc6bd..1b6125f2d9 100644
--- a/cpu/esp8266/esp-wifi/Makefile
+++ b/cpu/esp8266/esp-wifi/Makefile
@@ -1,7 +1,7 @@
 MODULE=esp_wifi
 
 # we have to do it in that way to avoid that pkg/lwip is found first
-CFLAGS += -I$(ESP8266_SDK_DIR)/components/lwip/lwip/src/include
-CFLAGS += -I$(ESP8266_SDK_DIR)/components/lwip/port/esp8266/include/
+CFLAGS += -I$(ESP8266_RTOS_SDK_DIR)/components/lwip/lwip/src/include
+CFLAGS += -I$(ESP8266_RTOS_SDK_DIR)/components/lwip/port/esp8266/include/
 
 include $(RIOTBASE)/Makefile.base
diff --git a/cpu/esp8266/vendor/esp-idf/esp8266/source/Makefile b/cpu/esp8266/vendor/esp-idf/esp8266/source/Makefile
index 77301c360a..474ca6e6d1 100644
--- a/cpu/esp8266/vendor/esp-idf/esp8266/source/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/esp8266/source/Makefile
@@ -2,5 +2,5 @@ MODULE=esp_idf_esp8266
 
 include $(RIOTBASE)/Makefile.base
 
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/esp8266/source
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/util/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/esp8266/source
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/util/include
diff --git a/cpu/esp8266/vendor/esp-idf/nvs_flash/Makefile b/cpu/esp8266/vendor/esp-idf/nvs_flash/Makefile
index 2bac3b2a86..83332d4b1b 100644
--- a/cpu/esp8266/vendor/esp-idf/nvs_flash/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/nvs_flash/Makefile
@@ -5,5 +5,5 @@ include $(RIOTBASE)/Makefile.base
 CFLAGS   += -DESP_PLATFORM
 CXXFLAGS += -std=c++11
 INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/log/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/nvs_flash/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/spi_flash/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/nvs_flash/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/spi_flash/include
diff --git a/cpu/esp8266/vendor/esp-idf/nvs_flash/src/Makefile b/cpu/esp8266/vendor/esp-idf/nvs_flash/src/Makefile
index 67dd77df96..315ae9edaf 100644
--- a/cpu/esp8266/vendor/esp-idf/nvs_flash/src/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/nvs_flash/src/Makefile
@@ -4,5 +4,5 @@ include $(RIOTBASE)/Makefile.base
 
 CFLAGS += -DESP_PLATFORM -DNVS_CRC_HEADER_FILE=\"crc.h\"
 CXXFLAGS += -std=c++11
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/nvs_flash/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/util/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/nvs_flash/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/util/include
diff --git a/cpu/esp8266/vendor/esp-idf/spi_flash/Makefile b/cpu/esp8266/vendor/esp-idf/spi_flash/Makefile
index 8bc13e48c9..9f729dce41 100644
--- a/cpu/esp8266/vendor/esp-idf/spi_flash/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/spi_flash/Makefile
@@ -2,4 +2,4 @@ MODULE=esp_idf_spi_flash
 
 include $(RIOTBASE)/Makefile.base
 
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/bootloader_support/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/bootloader_support/include
diff --git a/cpu/esp8266/vendor/esp-idf/util/src/Makefile b/cpu/esp8266/vendor/esp-idf/util/src/Makefile
index 2b4fc64e92..ebf2ebba1d 100644
--- a/cpu/esp8266/vendor/esp-idf/util/src/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/util/src/Makefile
@@ -2,4 +2,4 @@ MODULE=esp_idf_util
 
 include $(RIOTBASE)/Makefile.base
 
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/util/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/util/include
diff --git a/cpu/esp8266/vendor/esp-idf/wpa_supplicant/port/Makefile b/cpu/esp8266/vendor/esp-idf/wpa_supplicant/port/Makefile
index 40dd090754..1280d9b90a 100644
--- a/cpu/esp8266/vendor/esp-idf/wpa_supplicant/port/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/wpa_supplicant/port/Makefile
@@ -5,8 +5,8 @@ include $(RIOTBASE)/Makefile.base
 # we have to do it in that way to avoid that $(RIOTBASE)/sys/include/crypto
 # is found first
 INCLUDES  = -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/wpa_supplicant/port/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/wpa_supplicant/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/wpa_supplicant/port/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/wpa_supplicant/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/wpa_supplicant/port/include
 CFLAGS += -D__ets__ -DESPRESSIF_USE -DESP_PLATFORM=1
 CFLAGS += -Wno-strict-aliasing
 
diff --git a/cpu/esp8266/vendor/esp-idf/wpa_supplicant/src/crypto/Makefile b/cpu/esp8266/vendor/esp-idf/wpa_supplicant/src/crypto/Makefile
index 287f1eae3b..5763af65ed 100644
--- a/cpu/esp8266/vendor/esp-idf/wpa_supplicant/src/crypto/Makefile
+++ b/cpu/esp8266/vendor/esp-idf/wpa_supplicant/src/crypto/Makefile
@@ -6,8 +6,8 @@ include $(RIOTBASE)/Makefile.base
 # is found first
 INCLUDES  = -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/wpa_supplicant/include
 INCLUDES += -I$(RIOTCPU)/$(CPU)/vendor/esp-idf/wpa_supplicant/port/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/wpa_supplicant/include
-INCLUDES += -I$(ESP8266_SDK_DIR)/components/wpa_supplicant/port/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/wpa_supplicant/include
+INCLUDES += -I$(ESP8266_RTOS_SDK_DIR)/components/wpa_supplicant/port/include
 CFLAGS += -D__ets__ -DESPRESSIF_USE -DESP_PLATFORM=1
 CFLAGS += -Wno-strict-aliasing