diff --git a/Makefile b/Makefile
index dd2fbce..9e3d2f0 100644
--- a/Makefile
+++ b/Makefile
@@ -107,19 +107,19 @@ firmware/firmware.bin: firmware/firmware.elf
 	chmod -x $@
 
 firmware/firmware.elf: $(FIRMWARE_OBJS) $(TEST_OBJS) firmware/sections.lds
-	$(TOOLCHAIN_PREFIX)gcc -Os -ffreestanding -nostdlib -o $@ \
-		-Wl,-Bstatic,-T,firmware/sections.lds,-Map,firmware/firmware.map,--strip-debug \
+	$(TOOLCHAIN_PREFIX)gcc -Os -mabi=ilp32 -march=rv32im$(subst C,c,$(COMPRESSED_ISA)) -ffreestanding -nostdlib -o $@ \
+		-Wl,--build-id=none,-Bstatic,-T,firmware/sections.lds,-Map,firmware/firmware.map,--strip-debug \
 		$(FIRMWARE_OBJS) $(TEST_OBJS) -lgcc
 	chmod -x $@
 
 firmware/start.o: firmware/start.S
-	$(TOOLCHAIN_PREFIX)gcc -c -march=rv32im$(subst C,c,$(COMPRESSED_ISA)) -o $@ $<
+	$(TOOLCHAIN_PREFIX)gcc -c -mabi=ilp32 -march=rv32im$(subst C,c,$(COMPRESSED_ISA)) -o $@ $<
 
 firmware/%.o: firmware/%.c
-	$(TOOLCHAIN_PREFIX)gcc -c -march=rv32i$(subst C,c,$(COMPRESSED_ISA)) -Os --std=c99 $(GCC_WARNS) -ffreestanding -nostdlib -o $@ $<
+	$(TOOLCHAIN_PREFIX)gcc -c -mabi=ilp32 -march=rv32i$(subst C,c,$(COMPRESSED_ISA)) -Os --std=c99 $(GCC_WARNS) -ffreestanding -nostdlib -o $@ $<
 
 tests/%.o: tests/%.S tests/riscv_test.h tests/test_macros.h
-	$(TOOLCHAIN_PREFIX)gcc -c -march=rv32im -o $@ -DTEST_FUNC_NAME=$(notdir $(basename $<)) \
+	$(TOOLCHAIN_PREFIX)gcc -c -mabi=ilp32 -march=rv32im -o $@ -DTEST_FUNC_NAME=$(notdir $(basename $<)) \
 		-DTEST_FUNC_TXT='"$(notdir $(basename $<))"' -DTEST_FUNC_RET=$(notdir $(basename $<))_ret $<
 
 download-tools:
diff --git a/README.md b/README.md
index 3f41f0c..bcd8fa1 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,9 @@ contains a built-in interrupt controller.
 Tools (gcc, binutils, etc..) can be obtained via the [RISC-V Website](https://riscv.org/software-status/).
 The examples bundled with PicoRV32 expect various RV32 toolchains to be installed in `/opt/riscv32i[m][c]`. See
 the [build instructions below](#building-a-pure-rv32i-toolchain) for details.
+Many Linux distributions now include the tools for RISC-V (for example
+Ubuntu 20.04 has `gcc-riscv64-unknown-elf`). To compile using those set
+`TOOLCHAIN_PREFIX` accordingly (eg. `make TOOLCHAIN_PREFIX=riscv64-unknown-elf-`).
 
 PicoRV32 is free and open hardware licensed under the [ISC license](http://en.wikipedia.org/wiki/ISC_license)
 (a license that is similar in terms to the MIT license or the 2-clause BSD license).
diff --git a/picosoc/Makefile b/picosoc/Makefile
index 2f40df4..9c80745 100644
--- a/picosoc/Makefile
+++ b/picosoc/Makefile
@@ -40,7 +40,7 @@ hx8kdemo_sections.lds: sections.lds
 	$(CROSS)cpp -P -DHX8KDEMO -o $@ $^
 
 hx8kdemo_fw.elf: hx8kdemo_sections.lds start.s firmware.c
-	$(CROSS)gcc $(CFLAGS) -DHX8KDEMO -march=rv32imc -Wl,-Bstatic,-T,hx8kdemo_sections.lds,--strip-debug -ffreestanding -nostdlib -o hx8kdemo_fw.elf start.s firmware.c
+	$(CROSS)gcc $(CFLAGS) -DHX8KDEMO -mabi=ilp32 -march=rv32imc -Wl,--build-id=none,-Bstatic,-T,hx8kdemo_sections.lds,--strip-debug -ffreestanding -nostdlib -o hx8kdemo_fw.elf start.s firmware.c
 
 hx8kdemo_fw.hex: hx8kdemo_fw.elf
 	$(CROSS)objcopy -O verilog hx8kdemo_fw.elf hx8kdemo_fw.hex
@@ -86,7 +86,7 @@ icebreaker_sections.lds: sections.lds
 	$(CROSS)cpp -P -DICEBREAKER -o $@ $^
 
 icebreaker_fw.elf: icebreaker_sections.lds start.s firmware.c
-	$(CROSS)gcc $(CFLAGS) -DICEBREAKER -march=rv32ic -Wl,-Bstatic,-T,icebreaker_sections.lds,--strip-debug -ffreestanding -nostdlib -o icebreaker_fw.elf start.s firmware.c
+	$(CROSS)gcc $(CFLAGS) -DICEBREAKER -mabi=ilp32 -march=rv32ic -Wl,-Bstatic,-T,icebreaker_sections.lds,--strip-debug -ffreestanding -nostdlib -o icebreaker_fw.elf start.s firmware.c
 
 icebreaker_fw.hex: icebreaker_fw.elf
 	$(CROSS)objcopy -O verilog icebreaker_fw.elf icebreaker_fw.hex