baohua@baohua-VirtualBox:~/develop/u-boot$ /usr/bin/qemu-system-arm -M vexpress-a9 -m 512M -kernel u-boot -nographic
pulseaudio: set_sink_input_volume() failed
pulseaudio: Reason: Invalid argument
pulseaudio: set_sink_input_mute() failed
pulseaudio: Reason: Invalid argument


U-Boot 2017.03-00270-g5cf618e (Mar 31 2017 - 16:54:14 +0800)

DRAM:  512 MiB
WARNING: Caches not enabled
Flash: 256 MiB
MMC:   MMC: 0
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   smc911x-0
Hit any key to stop autoboot:  0 
=>