diff --git a/Makefile b/Makefile
index 6af42fdb79..00dfaf6225 100644
--- a/Makefile
+++ b/Makefile
@@ -182,9 +182,9 @@ bloaty: ## run bloaty size profiler
 	bloaty -d compileunits -n 0 -s file $(FIRMWARE_BUILD_DIR)/firmware.elf | less
 
 sizecheck: ## check sizes of binary files
-	test $(BOARDLOADER_MAXSIZE) -ge $(shell stat -c%s $(BOARDLOADER_BUILD_DIR)/boardloader.bin)
-	test $(BOOTLOADER_MAXSIZE) -ge $(shell stat -c%s $(BOOTLOADER_BUILD_DIR)/bootloader.bin)
-	test $(FIRMWARE_MAXSIZE) -ge $(shell stat -c%s $(FIRMWARE_BUILD_DIR)/firmware.bin)
+	test $(BOARDLOADER_MAXSIZE) -ge $(shell wc -c < $(BOARDLOADER_BUILD_DIR)/boardloader.bin)
+	test $(BOOTLOADER_MAXSIZE) -ge $(shell wc -c < $(BOOTLOADER_BUILD_DIR)/bootloader.bin)
+	test $(FIRMWARE_MAXSIZE) -ge $(shell wc -c < $(FIRMWARE_BUILD_DIR)/firmware.bin)
 
 combine: ## combine boardloader + bootloader + prodtest into one combined image
 	./tools/combine_firmware \
diff --git a/SConscript.firmware b/SConscript.firmware
index a33b90daf7..e048627b2a 100644
--- a/SConscript.firmware
+++ b/SConscript.firmware
@@ -430,6 +430,6 @@ program_bin = env.Command(
     action=[
         '$OBJCOPY -O binary -j .vendorheader -j .header -j .flash -j .data $SOURCE $TARGET',
         '$BINCTL $TARGET -h',
-        'dd if=$TARGET of=build/firmware/header.tosign bs=1 count=1024 skip=`stat -c%s embed/firmware/vendorheader.bin`',
+        'dd if=$TARGET of=build/firmware/header.tosign bs=1 count=1024 skip=`wc -c < embed/firmware/vendorheader.bin | tr -d " "`',
         '$BINCTL $TARGET -s 1:2 `$COMBINE_SIGN firmware build/firmware/header.tosign 4747474747474747474747474747474747474747474747474747474747474747 4848484848484848484848484848484848484848484848484848484848484848`',
     ], )
diff --git a/SConscript.prodtest b/SConscript.prodtest
index de82418be9..456c8aae19 100644
--- a/SConscript.prodtest
+++ b/SConscript.prodtest
@@ -154,6 +154,6 @@ program_bin = env.Command(
     action=[
         '$OBJCOPY -O binary -j .vendorheader -j .header -j .flash -j .data $SOURCE $TARGET',
         '$BINCTL $TARGET -h',
-        'dd if=$TARGET of=build/prodtest/header.tosign bs=1 count=1024 skip=`stat -c%s embed/firmware/vendorheader.bin`',
+        'dd if=$TARGET of=build/prodtest/header.tosign bs=1 count=1024 skip=`wc -c < embed/firmware/vendorheader.bin | tr -d " "`',
         '$BINCTL $TARGET -s 1:2 `$COMBINE_SIGN firmware build/prodtest/header.tosign 4747474747474747474747474747474747474747474747474747474747474747 4848484848484848484848484848484848484848484848484848484848484848`',
     ], )