diff --git a/makefiles/arch/mips.inc.mk b/makefiles/arch/mips.inc.mk
index 9153763f85..eca7258865 100644
--- a/makefiles/arch/mips.inc.mk
+++ b/makefiles/arch/mips.inc.mk
@@ -1,5 +1,5 @@
 # Target triple for the build.
-export TARGET_ARCH ?= mips-mti-elf
+TARGET_ARCH ?= mips-mti-elf
 
 ABI = 32
 
diff --git a/makefiles/arch/msp430.inc.mk b/makefiles/arch/msp430.inc.mk
index 61a6c28764..e500c86087 100644
--- a/makefiles/arch/msp430.inc.mk
+++ b/makefiles/arch/msp430.inc.mk
@@ -1,5 +1,5 @@
 # Target architecture for the build. Use msp430 if you are unsure.
-export TARGET_ARCH ?= msp430
+TARGET_ARCH ?= msp430
 
 # define build specific options
 CFLAGS_CPU   = -mmcu=$(CPU_MODEL)
diff --git a/makefiles/arch/riscv.inc.mk b/makefiles/arch/riscv.inc.mk
index db5d7cfcd2..120abb67dd 100644
--- a/makefiles/arch/riscv.inc.mk
+++ b/makefiles/arch/riscv.inc.mk
@@ -1,5 +1,5 @@
 # Target architecture for the build.
-export TARGET_ARCH ?= riscv-none-embed
+TARGET_ARCH ?= riscv-none-embed
 
 # define build specific options
 CFLAGS_CPU   = -march=rv32imac -mabi=ilp32 -mcmodel=medlow -msmall-data-limit=8