diff --git a/src/arch/8051/arch.mk b/src/arch/8051/arch.mk
index 2c45d7e..bcd5b16 100644
--- a/src/arch/8051/arch.mk
+++ b/src/arch/8051/arch.mk
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
 CC=sdcc -mmcs51 --model-large --code-size $(CODE_SIZE) --xram-size $(SRAM_SIZE) --Werror
-OBJ=$(patsubst src/%.c,$(BUILD)/%.rel,$(SRC))
+OBJ=$(sort $(patsubst src/%.c,$(BUILD)/%.rel,$(SRC)))
 
 # Run EC rom in simulator
 sim: $(BUILD)/ec.rom
diff --git a/src/arch/avr/arch.mk b/src/arch/avr/arch.mk
index a847964..08dd6ec 100644
--- a/src/arch/avr/arch.mk
+++ b/src/arch/avr/arch.mk
@@ -2,7 +2,7 @@
 
 CC=avr-gcc -mmcu=$(EC)
 CFLAGS+=-Os -fstack-usage -Wall -Werror -Wl,--gc-sections -Wl,-u,vfprintf -lprintf_flt
-OBJ=$(patsubst src/%.c,$(BUILD)/%.o,$(SRC))
+OBJ=$(sort $(patsubst src/%.c,$(BUILD)/%.o,$(SRC)))
 
 # Run EC rom in simulator
 sim: $(BUILD)/ec.elf
diff --git a/src/board/system76/common/flash/flash.mk b/src/board/system76/common/flash/flash.mk
index 9988b70..212ee69 100644
--- a/src/board/system76/common/flash/flash.mk
+++ b/src/board/system76/common/flash/flash.mk
@@ -17,7 +17,7 @@ FLASH_INCLUDE+=$(wildcard $(FLASH_DIR)/include/flash/*.h) $(FLASH_DIR)/flash.mk
 FLASH_CFLAGS+=-I$(FLASH_DIR)/include -D__FLASH__
 
 FLASH_BUILD=$(BUILD)/flash
-FLASH_OBJ=$(patsubst src/%.c,$(FLASH_BUILD)/%.rel,$(FLASH_SRC))
+FLASH_OBJ=$(sort $(patsubst src/%.c,$(FLASH_BUILD)/%.rel,$(FLASH_SRC)))
 FLASH_CC=\
 	sdcc \
 	-mmcs51 \
diff --git a/src/board/system76/common/scratch/scratch.mk b/src/board/system76/common/scratch/scratch.mk
index 6ec36dd..5fa35e8 100644
--- a/src/board/system76/common/scratch/scratch.mk
+++ b/src/board/system76/common/scratch/scratch.mk
@@ -20,7 +20,7 @@ SCRATCH_SRC+=\
 	$(SYSTEM76_COMMON_DIR)/smfi.c
 
 SCRATCH_BUILD=$(BUILD)/scratch
-SCRATCH_OBJ=$(patsubst src/%.c,$(SCRATCH_BUILD)/%.rel,$(SCRATCH_SRC))
+SCRATCH_OBJ=$(sort $(patsubst src/%.c,$(SCRATCH_BUILD)/%.rel,$(SCRATCH_SRC)))
 SCRATCH_CC=\
 	sdcc \
 	-mmcs51 \