diff --git a/src/arch/8051/arch.mk b/src/arch/8051/arch.mk
index 1d7ef6c..41616db 100644
--- a/src/arch/8051/arch.mk
+++ b/src/arch/8051/arch.mk
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
-CC=sdcc -mmcs51 --model-large --Werror
+CC=sdcc -mmcs51 --model-large --xram-size $(SRAM_SIZE) --Werror
 OBJ=$(patsubst src/%.c,$(BUILD)/%.rel,$(SRC))
 
 # Run EC rom in simulator
diff --git a/src/ec/it5570e/ec.mk b/src/ec/it5570e/ec.mk
index fa1f312..5067487 100644
--- a/src/ec/it5570e/ec.mk
+++ b/src/ec/it5570e/ec.mk
@@ -1,3 +1,8 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
 ARCH=8051
+
+# SRAM is 6144 bytes, only 4096 bytes are mapped at address 0. Region at
+# 0x0E00-0x1000 is used for AP communication. So this is brought down to 2048,
+# which matches it8587e limits
+SRAM_SIZE=2048
diff --git a/src/ec/it8587e/ec.mk b/src/ec/it8587e/ec.mk
index fa1f312..1ce94c6 100644
--- a/src/ec/it8587e/ec.mk
+++ b/src/ec/it8587e/ec.mk
@@ -1,3 +1,6 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
 ARCH=8051
+
+# SRAM is 4096 bytes, but SRAM at address 2048 is used for scratch ROM
+SRAM_SIZE=2048