diff --git a/plat/hisilicon/hikey/platform.mk b/plat/hisilicon/hikey/platform.mk
index d43b20b3ee1b35646867fcfa17564a175d4295a9..36629140558e99e97bdc95f36d1d40061552a24d 100644
--- a/plat/hisilicon/hikey/platform.mk
+++ b/plat/hisilicon/hikey/platform.mk
@@ -9,11 +9,11 @@ LOAD_IMAGE_V2	:=	1
 
 # On Hikey, the TSP can execute from TZC secure area in DRAM (default)
 # or SRAM.
-HIKEY_TSP_RAM_LOCATION	:=	dram
+HIKEY_TSP_RAM_LOCATION	?=	dram
 ifeq (${HIKEY_TSP_RAM_LOCATION}, dram)
   HIKEY_TSP_RAM_LOCATION_ID = HIKEY_DRAM_ID
 else ifeq (${HIKEY_TSP_RAM_LOCATION}, sram)
-  HIKEY_TSP_RAM_LOCATION_ID := HIKEY_SRAM_ID
+  HIKEY_TSP_RAM_LOCATION_ID = HIKEY_SRAM_ID
 else
   $(error "Currently unsupported HIKEY_TSP_RAM_LOCATION value")
 endif
diff --git a/plat/hisilicon/hikey960/platform.mk b/plat/hisilicon/hikey960/platform.mk
index cd063058ebb6354ef446521050ac9a498f0fdf72..ffe10738f5d5e4f40943141ee3cf2963d5454290 100644
--- a/plat/hisilicon/hikey960/platform.mk
+++ b/plat/hisilicon/hikey960/platform.mk
@@ -8,11 +8,11 @@
 LOAD_IMAGE_V2	:=	1
 
 # On Hikey960, the TSP can execute from TZC secure area in DRAM.
-HIKEY960_TSP_RAM_LOCATION	:=	dram
+HIKEY960_TSP_RAM_LOCATION	?=	dram
 ifeq (${HIKEY960_TSP_RAM_LOCATION}, dram)
   HIKEY960_TSP_RAM_LOCATION_ID = HIKEY960_DRAM_ID
 else ifeq (${HIKEY960_TSP_RAM_LOCATION}, sram)
-  HIKEY960_TSP_RAM_LOCATION_ID := HIKEY960_SRAM_ID
+  HIKEY960_TSP_RAM_LOCATION_ID = HIKEY960_SRAM_ID
 else
   $(error "Currently unsupported HIKEY960_TSP_RAM_LOCATION value")
 endif
diff --git a/plat/hisilicon/poplar/platform.mk b/plat/hisilicon/poplar/platform.mk
index 58f21ed1d91b87dd837a00984b33e323964f7a20..7c8027eada793d832c7f53fa4403af0c4b28e15b 100644
--- a/plat/hisilicon/poplar/platform.mk
+++ b/plat/hisilicon/poplar/platform.mk
@@ -8,11 +8,11 @@
 LOAD_IMAGE_V2	:=	1
 
 # On Poplar, the TSP can execute from TZC secure area in DRAM.
-POPLAR_TSP_RAM_LOCATION	:=	dram
+POPLAR_TSP_RAM_LOCATION	?=	dram
 ifeq (${POPLAR_TSP_RAM_LOCATION}, dram)
   POPLAR_TSP_RAM_LOCATION_ID = POPLAR_DRAM_ID
 else ifeq (${POPLAR_TSP_RAM_LOCATION}, sram)
-  POPLAR_TSP_RAM_LOCATION_ID := POPLAR_SRAM_ID
+  POPLAR_TSP_RAM_LOCATION_ID = POPLAR_SRAM_ID
 else
   $(error "Currently unsupported POPLAR_TSP_RAM_LOCATION value")
 endif