diff --git a/scripts/icestorm/Makefile b/scripts/icestorm/Makefile
index ea4efff..e2771b1 100644
--- a/scripts/icestorm/Makefile
+++ b/scripts/icestorm/Makefile
@@ -4,7 +4,7 @@ TOOLCHAIN_PREFIX = riscv32-unknown-elf-
 all: example.bin
 
 firmware.elf: firmware.S firmware.c firmware.lds
-	$(TOOLCHAIN_PREFIX)gcc -Os -ffreestanding -nostdlib -o $@ firmware.S firmware.c \
+	$(TOOLCHAIN_PREFIX)gcc -march=rv32i -Os -ffreestanding -nostdlib -o $@ firmware.S firmware.c \
 			--std=gnu99 -Wl,-Bstatic,-T,firmware.lds,-Map,firmware.map,--strip-debug -lgcc
 	chmod -x $@