Android 4.3 emulator screen stay black and qemu: could not load initrd 'ramdisk.img'

After building the 4.3 source code, I try to run the emulator with self-compiled system.img, userdata.img and ramdisk.img, but the emulator's screen stays black and adb devices shows offline, no output.

Try to use "kernel-qemu-armv7" instead of "kernel-qemu", solve the balck screen.

But there is still "qemu: could not load initrd 'ramdisk.img', after trying several times follow the guide on internet:

1. chmod 777 -R * in ramdisk.img's path.

2. using full path in -ramdisk

below list my cmd:

/AOSP/out/host/linux-x86/bin/./emulator -kernel /AOSP/prebuilts/qemu-kernel/arm/kernel-qemu-armv7 -sysdir /AOSP/out/target/product/generic/ -system system.img -data userdata.img -ramdisk /AOSP/out/target/product/generic/ramdisk.img -skindir skins/ -skin HVGA -partition-size 768

the skins/ folder is copied from SDK path.