diff --git a/Makefile b/Makefile
index ee469ab..da42271 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 
-RISCV_GNU_TOOLCHAIN_REV = 34db4e0
+RISCV_GNU_TOOLCHAIN_REV = 13f52d2
 GCC_URL = http://mirrors.kernel.org/gnu/gcc/gcc-6.1.0/gcc-6.1.0.tar.gz
 NEWLIB_URL = ftp://sourceware.org/pub/newlib/newlib-2.2.0.tar.gz
 BINUTILS_URL = http://mirrors.kernel.org/gnu/binutils/binutils-2.26.tar.gz
@@ -91,16 +91,16 @@ build-$(1)-tools-bh:
 	set -ex; if ! test -d riscv-gnu-toolchain-$(1); then git clone https://github.com/riscv/riscv-gnu-toolchain riscv-gnu-toolchain-$(1); \
 		else cd riscv-gnu-toolchain-$(1); git checkout master; git pull; fi
 	set -ex; cd riscv-gnu-toolchain-$(1); rm -rf build; git checkout $(RISCV_GNU_TOOLCHAIN_REV); mkdir -p build
-	set -ex; cd riscv-gnu-toolchain-$(1)/build; ../configure --with-xlen=32 --with-arch=$(2) --prefix=/opt/$(1) --disable-float --disable-atomic
+	set -ex; cd riscv-gnu-toolchain-$(1)/build; ../configure --with-arch=$(2) --prefix=/opt/$(1)
 	+set -ex; cd riscv-gnu-toolchain-$(1)/build; make
 
 .PHONY: build-$(1)-tools
 endef
 
-$(eval $(call build_tools_template,riscv32i,I))
-$(eval $(call build_tools_template,riscv32ic,IC))
-$(eval $(call build_tools_template,riscv32im,IM))
-$(eval $(call build_tools_template,riscv32imc,IMC))
+$(eval $(call build_tools_template,riscv32i,RV32I))
+$(eval $(call build_tools_template,riscv32ic,RV32IC))
+$(eval $(call build_tools_template,riscv32im,RV32IM))
+$(eval $(call build_tools_template,riscv32imc,RV32IMC))
 
 build-tools:
 	@echo "This will remove all existing data from /opt/riscv32i, /opt/riscv32ic, /opt/riscv32im, and /opt/riscv32imc."
diff --git a/README.md b/README.md
index b223f62..cdd6776 100644
--- a/README.md
+++ b/README.md
@@ -318,9 +318,9 @@ any other ALU operation.
 The following dhrystone benchmark results are for a core with enabled
 `ENABLE_MUL`, `ENABLE_DIV`, and `BARREL_SHIFTER` options.
 
-Dhrystone benchmark results: 0.395 DMIPS/MHz (695 Dhrystones/Second/MHz)
+Dhrystone benchmark results: 0.406 DMIPS/MHz (715 Dhrystones/Second/MHz)
 
-For the Dhrystone benchmark the average CPI is 4.047.
+For the Dhrystone benchmark the average CPI is 4.072.
 
 
 PicoRV32 Native Memory Interface
@@ -578,10 +578,10 @@ pure RV32I target, and install it in `/opt/riscv32i`:
 
     git clone https://github.com/riscv/riscv-gnu-toolchain riscv-gnu-toolchain-rv32i
     cd riscv-gnu-toolchain-rv32i
-    git checkout 34db4e0
+    git checkout 13f52d2
 
     mkdir build; cd build
-    ../configure --with-xlen=32 --with-arch=I --prefix=/opt/riscv32i --disable-float --disable-atomic
+    ../configure --with-arch=RV32I --prefix=/opt/riscv32i
     make -j$(nproc)
 
 The commands will all be named using the prefix `riscv32-unknown-elf-`, which
@@ -604,7 +604,7 @@ By default calling any of those make targets will (re-)download the toolchain
 sources. Run `make download-tools` to download the sources to `/var/cache/distfiles/`
 once in advance.
 
-*Note: This instructions are for git rev 34db4e0 (2016-05-05) of riscv-gnu-toolchain.*
+*Note: This instructions are for git rev 13f52d2 (2016-05-31) of riscv-gnu-toolchain.*
 
 
 Evaluation: Timing and Utilization on Xilinx 7-Series FPGAs