diff --git a/Makefile b/Makefile
index cfa53f9..a379dad 100644
--- a/Makefile
+++ b/Makefile
@@ -42,4 +42,5 @@ $(OUT)fw-stock.bin $(OUT)fw-user.bin: $(wildcard firmware/*.*)
 	@mkdir -p $(OUT)
 	cd firmware && ./build.sh
 	cp -f firmware/build/fw-stock.bin $(OUT)fw-stock.bin
+	cp -f firmware/build/fw-stock-proto-v3.bin $(OUT)fw-stock-proto-v3.bin
 	cp -f firmware/build/fw-user.bin $(OUT)fw-user.bin
diff --git a/firmware/build.sh b/firmware/build.sh
index 29d60b8..1b3e0f6 100755
--- a/firmware/build.sh
+++ b/firmware/build.sh
@@ -26,6 +26,26 @@ sdcc \
 	-I. \
 	-DFW_REVISION_STR="\"$(git describe) $(git log -1 --format=%cd --date=iso)\"" \
 	-DCONFIG_STOCK_FW=1 \
+	-DCONFIG_I2C_A=0 \
+	build/stock-ivt.rel main.c \
+	-o build/fw-stock-proto-v3.ihx
+
+hex2bin fw-stock-proto-v3
+
+# build stock FW (hw mod)
+
+cpp -P -nostdinc -I. -D__ASM_ONLY__ stock-ivt.asm build/stock-ivt.asm
+sdas8051 -plosgff build/stock-ivt.rel build/stock-ivt.asm
+
+echo "Stock FW Final"
+sdcc \
+	-mmcs51 --iram-size 256 --xram-size 2048 \
+	--code-size 0x2000 --code-loc 0x2130 \
+	-Wl-bIVECT=0x2000 \
+	-I. \
+	-DFW_REVISION_STR="\"$(git describe) $(git log -1 --format=%cd --date=iso)\"" \
+	-DCONFIG_STOCK_FW=1 \
+	-DCONFIG_I2C_A=1 \
 	build/stock-ivt.rel main.c \
 	-o build/fw-stock.ihx