diff --git a/.gitignore b/.gitignore
index f588e07..0ac0597 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,4 +15,5 @@ boot_code/*.txt
 system/boot_code.bin
 system/boot_code.txt
 system/obj_dir/
+system/simplified_ucode.txt
 tools/*svg
diff --git a/boot_code/colored_led.asm b/boot_code/colored_led.asm
index 7055c3e..0b41e93 100644
--- a/boot_code/colored_led.asm
+++ b/boot_code/colored_led.asm
@@ -1,4 +1,7 @@
+INCLUDE dos_layer.asm
+
 .org 0x100
+mov sp,#STACK
 
 MAIN_LOOP:
 MOV DL,#0xF0
@@ -16,11 +19,14 @@ out byte #0xB0
 MOV SI,#RESERVED
 MOV DI,#RESERVED
 MOV AL,#0x68 ; 'h'
-MOV [DI],AL
+STOSB
 MOV AL,#0x00
 MOV AL,[SI]
 
-out byte #0xA5
+MOV AH,#0x02
+MOV DL,AL
+INT #0x21
+
 MOV AL,#0x65
 out byte #0xA5
 MOV AL,#0x6c
@@ -47,6 +53,8 @@ MOV AX,#0x0100
 JMP AX
 
 RESERVED: DB 0x48 ; 'H'
+.BLKB 200
+STACK:
 
 .ORG 0xFFF0
 MOV AX,#0x0100
diff --git a/system/Makefile b/system/Makefile
index 4397a85..45d13f7 100644
--- a/system/Makefile
+++ b/system/Makefile
@@ -71,8 +71,11 @@ ECP5_TARGETS+=abc.history # created from yosys
 
 EXTRA_SYNTHESIS_SOURCES=peripherals/I2C_driver.v peripherals/ascii_to_HD44780_driver.v peripherals/pcf8574_for_HD44780.v
 
+simplified_ucode.txt:ucode.txt
+	${Q}tr 'x' '0' < $^ | sed 's@//.*@@' | grep ^@ |sort | sed 's/.* .//;s/ $$//' | tr -d _ > $@
+
 #TODO: we are relying on yosys to trim the input program txt file and hope its enough for the whole program...
-synth_ecp5.json: ${SOURCES} ${TOP_LEVEL_SOURCE} fpga_config/${FPGA_BOARD}/fpga_top.v ${EXTRA_SYNTHESIS_SOURCES} ${INCLUDES} ../boot_code/colored_led.txt
+synth_ecp5.json: ${SOURCES} ${TOP_LEVEL_SOURCE} fpga_config/${FPGA_BOARD}/fpga_top.v ${EXTRA_SYNTHESIS_SOURCES} ${INCLUDES} ../boot_code/colored_led.txt simplified_ucode.txt
 	${QUIET_YOSYS}
 	${Q} yosys -q -D BUILTIN_RAM=512 -D NOT_FULL -p 'read -sv '"${SOURCES} ${TOP_LEVEL_SOURCE} fpga_config/${FPGA_BOARD}/fpga_top.v ${EXTRA_SYNTHESIS_SOURCES} ; synth_ecp5 -json $@ -top fpga_top"
 
@@ -101,4 +104,4 @@ upload: upload_orangecrab
 .PHONY: clean
 clean:
 	$(call QUIET_CLEAN,system)
-	${Q}rm -rf ${SYSTEM_VVP} *.fst boot_code.txt boot_code.bin *memdump *memdumptxt obj_dir *json  ${ECP5_TARGETS}
+	${Q}rm -rf ${SYSTEM_VVP} *.fst boot_code.txt boot_code.bin *memdump *memdumptxt obj_dir *json simplified_ucode.txt ${ECP5_TARGETS}
diff --git a/system/decoder.v b/system/decoder.v
index eabc2fc..175832e 100644
--- a/system/decoder.v
+++ b/system/decoder.v
@@ -214,7 +214,7 @@ initial begin
 	end
 `else
 	//TODO: don't have it hard coded
-	$readmemb("ucode.txt",ucode_rom,0,`UCODE_SIZE-1);
+	$readmemb("simplified_ucode.txt",ucode_rom,0,`UCODE_SIZE-1);
 `endif
 end