diff --git a/firmware/Makefile b/firmware/Makefile
index f55badb..087f534 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -4,9 +4,9 @@ pcf_file = ./io.pcf
 
 SOURCES := $(wildcard *.v)
 top.bin: $(SOURCES)
-	yosys -p 'synth_ice40 -top top -json $(filename).json -blif $(filename).blif' -p 'ice40_opt' -p 'fsm_opt' $(filename).v
+	yosys -p 'synth_ice40 -abc2 -top top -json $(filename).json -blif $(filename).blif' -p 'opt' -p 'ice40_opt' -p 'fsm_opt' $(filename).v | grep -i warning
 	#nextpnr-ice40 --lp1k --package qn84 --json $(filename).json --pcf $(pcf_file) --asc $(filename).asc
-	nextpnr-ice40 --lp1k --package qn84 --json $(filename).json --pcf $(pcf_file) --asc $(filename).asc --freq 64 --parallel-refine --opt-timing --timing-allow-fail
+	false; while [ $$? != 0 ]; do nextpnr-ice40 --lp1k --package qn84 --json $(filename).json --pcf $(pcf_file) --asc $(filename).asc --freq 64 --opt-timing; done
 	#nextpnr-ice40 --json blinky.json --pcf blinky.pcf --asc blinky.asc --gui
 	icepack $(filename).asc $(filename).bin