diff --git a/boards/common/esp32/Makefile.include b/boards/common/esp32/Makefile.include
index 5087328682..9a4f711f06 100644
--- a/boards/common/esp32/Makefile.include
+++ b/boards/common/esp32/Makefile.include
@@ -1,6 +1,6 @@
 # the cpu to build for
-export CPU ?= esp32
-export CPU_MODEL ?= esp32
+export CPU = esp32
+export CPU_MODEL = esp32
 
 # configure the serial interface
 PORT_LINUX ?= /dev/ttyUSB0
diff --git a/boards/common/esp8266/Makefile.include b/boards/common/esp8266/Makefile.include
index 44a141a366..63a50b28e8 100644
--- a/boards/common/esp8266/Makefile.include
+++ b/boards/common/esp8266/Makefile.include
@@ -1,6 +1,6 @@
 # the cpu to build for
-export CPU ?= esp8266
-export CPU_MODEL ?= esp8266
+export CPU = esp8266
+export CPU_MODEL = esp8266
 
 # configure the serial interface
 PORT_LINUX ?= /dev/ttyUSB0
diff --git a/cpu/esp32/Makefile.include b/cpu/esp32/Makefile.include
index fdf445a7c0..983676e55d 100644
--- a/cpu/esp32/Makefile.include
+++ b/cpu/esp32/Makefile.include
@@ -59,7 +59,6 @@ PSEUDOMODULES += esp_spi_ram
 PSEUDOMODULES += esp_spiffs
 PSEUDOMODULES += esp_wifi_any
 
-export CPU ?= esp32
 export TARGET_ARCH ?= xtensa-esp32-elf
 export ESPTOOL ?= $(ESP32_SDK_DIR)/components/esptool_py/esptool/esptool.py