diff --git a/.travis.yml b/.travis.yml
index 98fb352..02df662 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ dist: xenial
 
 language: rust
 
-rust: nightly-2019-01-01
+rust: nightly-2019-02-15
 
 os:
   - linux
@@ -25,6 +25,7 @@ env:
   matrix:
     - ARCH="riscv64"
     - ARCH="riscv64" OPTS="board=k210"
+    - ARCH="riscv64" OPTS="board=u540"
     - ARCH="riscv32"
     - ARCH="riscv32" OPTS="m_mode=1"
     - ARCH="x86_64"
@@ -32,17 +33,18 @@ env:
 
 install:
   - if [ $ARCH = riscv32 ] || [ $ARCH = riscv64 ]; then
-      [ $TRAVIS_OS_NAME = linux ] && export FILE="riscv64-unknown-elf-gcc-8.1.0-2018.12.0-x86_64-linux-ubuntu14";
-      [ $TRAVIS_OS_NAME = osx   ] && export FILE="riscv64-unknown-elf-gcc-8.1.0-2018.12.0-x86_64-apple-darwin";
+      [ $TRAVIS_OS_NAME = linux ] && export FILE="riscv64-unknown-elf-gcc-8.1.0-2019.01.0-x86_64-linux-ubuntu14";
+      [ $TRAVIS_OS_NAME = osx   ] && export FILE="riscv64-unknown-elf-gcc-8.1.0-2019.01.0-x86_64-apple-darwin";
       wget https://static.dev.sifive.com/dev-tools/$FILE.tar.gz;
       tar xf $FILE.tar.gz;
       export PATH=$PATH:$PWD/$FILE/bin;
     fi
   - if [ $ARCH = aarch64 ]; then
     if [ $TRAVIS_OS_NAME = linux ]; then
-      wget https://developer.arm.com/-/media/Files/downloads/gnu-a/8.2-2018.11/gcc-arm-8.2-2018.11-x86_64-aarch64-elf.tar.xz;
-      tar -xvf gcc-arm-8.2-2018.11-x86_64-aarch64-elf.tar.xz;
-      export PATH=$PATH:$PWD/gcc-arm-8.2-2018.11-x86_64-aarch64-elf/bin;
+      export FILE="gcc-arm-8.2-2018.11-x86_64-aarch64-elf";
+      wget https://developer.arm.com/-/media/Files/downloads/gnu-a/8.2-2018.11/$FILE.tar.xz;
+      tar -xvf $FILE.tar.xz;
+      export PATH=$PATH:$PWD/$FILE/bin;
     elif [ $TRAVIS_OS_NAME = osx ]; then
       brew tap SergioBenitez/osxct;
       brew install aarch64-none-elf;
diff --git a/README.md b/README.md
index 6459588..2ecc046 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # rCore Plus
 
-[![Build Status](https://travis-ci.org/wangrunji0408/RustOS.svg?branch=master)](https://travis-ci.org/oscourse-tsinghua/RustOS)
+[![Build Status](https://travis-ci.org/oscourse-tsinghua/rcore_plus.svg?branch=master)](https://travis-ci.org/oscourse-tsinghua/rcore_plus)
 
 Rust version of THU [uCore OS Plus](https://github.com/chyyuu/ucore_os_plus).
 
@@ -8,7 +8,7 @@ Its former repo name is https://github.com/oscourse-tsinghua/RustOS .
 
 Going to be the next generation teaching operating system.
 
-Supported architectures: x86_64, RISCV32/64, AArch64， MIPS(future)
+Supported architectures: x86_64, RISCV32/64, AArch64, MIPS(future)
 
 Tested boards: QEMU, labeled-RISCV, K210, Raspberry Pi 3B+
 
@@ -20,12 +20,14 @@ Tested boards: QEMU, labeled-RISCV, K210, Raspberry Pi 3B+
 
 ### Environment
 
-* [Rust](https://www.rust-lang.org) toolchain at nightly-2019-01-01
+* [Rust](https://www.rust-lang.org) toolchain at nightly-2019-02-15
 * Cargo tools: [cargo-xbuild](https://github.com/rust-osdev/cargo-xbuild)
 * [QEMU](https://www.qemu.org) >= 3.1.0
 * [bootimage](https://github.com/rust-osdev/bootimage) (for x86_64)
 * [RISCV64 GNU toolchain](https://www.sifive.com/boards) (for riscv32/64)
-* [AArch64 GNU toolchain](https://web.stanford.edu/class/cs140e/assignments/0-blinky/) (for aarch64)
+* [AArch64 GNU toolchain](https://cs140e.sergio.bz/assignments/0-blinky/) (for aarch64)
+
+See [Travis script](./.travis.yml) for details.
 
 ### How to run
 
@@ -35,9 +37,9 @@ cargo install cargo-xbuild bootimage
 ```
 
 ```bash
-git clone https://github.com//oscourse-tsinghua/rcore_plus.git --recursive
+git clone https://github.com/oscourse-tsinghua/rcore_plus.git --recursive
 cd rcore_plus/kernel
-rustup override set nightly-2019-01-01
+rustup override set nightly-2019-02-15
 make run arch={riscv32,riscv64,x86_64,aarch64}
 ```
 
diff --git a/kernel/Makefile b/kernel/Makefile
index c011e0e..7538688 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -18,6 +18,7 @@
 #   graphic = on | off              enable/disable qemu graphical output
 #   board   = none                Running on QEMU
 #         | k210                Only available on riscv64, build without bbl, run on K210
+#         | u540                Only available on riscv64, run on HiFive U540, use Sv39
 #         | raspi3              Only available on aarch64, run on Raspberry Pi 3 Model B/B+
 #   m_mode                      Only available on riscv32, build for M-Mode, without MMU
 
@@ -90,14 +91,10 @@ endif
 else ifeq ($(arch), aarch64)
 qemu_opts += \
 	-machine $(board) \
-	-serial null -serial mon:stdio \
+	-serial null \
 	-kernel $(bin)
 endif
 
-ifneq ($(graphic), on)
-qemu_opts += -nographic
-endif
-
 ifdef d
 qemu_opts += -d $(d)
 endif