This is my first time to flash the AOSP building on the device. I just followed the google's instructions to download and build the Android source code. Since I have a Nexus 7 (2013), so I chose the target to "aosp_flo-userdebug" before starting to build. Then I ran "make" to build, and the building was successful.
After that I rebooted the device and went into the boot loader, flashed the device by command:
$ fastboot -w flashall
The flash succeed. Then after the device rebooted, it just stuck on the Google's logo screen and never continue. If I flash it back to the factory image, it can continue starting. So I think maybe there are some mistakes during the building or flashing that causes the problem. But I don't know how to find the problem.
I also tried to flash only system.img by:
$ fastboot flash system system.img
But it's till the same result. Hope someone can give me some suggestions. Thanks.
I resolved my problem eventually. In short, just because I missed the device specific binaries during the building.