Basic example, outputs work but inputs don't

examples/up5k/.gitignore

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+example.bin
+example.blif
+example.asc
+example.rpt

examples/up5k/Makefile

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+PROJ = example
+PIN_DEF = up5k.pcf
+DEVICE = up5k
+# Relative paths for easier development without messing with installed version
+ARACHNE = ../../../arachne-pnr/bin/arachne-pnr
+ARACHNE_ARGS = -c ../../icebox/chipdb-5k.txt
+ICEPACK = ../../icepack/icepack
+ICETIME = ../../icetime/icetime
+ICEPROG = ../../iceprog/iceprog
+
+all: $(PROJ).bin
+
+%.blif: %.v
+	yosys -p 'synth_ice40 -top top -blif $@' $<
+
+%.asc: $(PIN_DEF) %.blif
+	$(ARACHNE) $(ARACHNE_ARGS) -d $(subst up,,$(subst hx,,$(subst lp,,$(DEVICE)))) -o $@ -p $^
+
+%.bin: %.asc
+	$(ICEPACK) $< $@
+
+%.rpt: %.asc
+	$(ICETIME) -d $(DEVICE) -mtr $@ $<
+
+prog: $(PROJ).bin
+	$(ICEPROG) -S $<
+
+sudo-prog: $(PROJ).bin
+	@echo 'Executing prog as root!!!'
+	sudo $(ICEPROG) -S $<
+
+clean:
+	rm -f $(PROJ).blif $(PROJ).asc $(PROJ).rpt $(PROJ).bin
+
+.SECONDARY:
+.PHONY: all prog clean

examples/up5k/example.v

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+module top (
+	input  btn,
+	output LED0,
+	output LED1,
+);
+
+assign LED0 = !btn;
+assign LED1 = btn;
+
+endmodule

examples/up5k/up5k.pcf

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+set_io LED0 12
+set_io LED1 21
+set_io btn 26