1. 启动下面信息之后系统就挂掉了，没有继续输出信息
Switching to clocksource tcb_clksrc NET: Registered protocol family 2 IP route cache hash table entries: 1024 (order: 0, 4096 bytes) TCP established hash table entries: 4096 (order: 3, 32768 bytes) TCP bind hash table entries: 4096 (order: 2, 16384 bytes) TCP: Hash tables configured (established 4096 bind 4096) TCP reno registered UDP hash table entries: 256 (order: 0, 4096 bytes) UDP-Lite hash table entries: 256 (order: 0, 4096 bytes) NET: Registered protocol family 1 RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. Trying to unpack rootfs image as initramfs... rootfs image is not initramfs (no cpio magic); looks like an initrd
解决办法：
好吧，是我粗心，不ramdisk的大小设置得太大了，我在 u-boot 这样配置 bootargs 导致了上面的问题
set bootargs root=/dev/ram0 rw ramdisk_size=17912 initrd=0x21100000,64M console=ttyS0,115200n8
把 64M 改为 16M 就好了
2. Ramdisk 挂载失败
Ramdisk 挂载失败，并有类似的下面信息输出:
RAMDISK: gzip image found at block 0 RAMDISK: incomplete write (4485 != 32768) write error VFS: Mounted root (ext2 filesystem) on device 1:0. attempt to access beyond end of device ram0: rw=0, want=112684, limit=35824 EXT2-fs (ram0): error: ext2_get_inode: unable to read inode block - inode=230, block=56341 EXT2-fs (ram0): error: remounting filesystem read-only devtmpfs: error mounting -5 Freeing init memory: 136K attempt to access beyond end of device ram0: rw=0, want=48300, limit=35824 EXT2-fs (ram0): error: ext2_get_inode: unable to read inode block - inode=97, block=24149 EXT2-fs (ram0): error: remounting filesystem read-only attempt to access beyond end of device
一般是制作 ramdisk 的时候指定的大小太大了，比如用下面的命令制作 ramdisk
genext2fs -b 102400 -d rootfs ramdisk.image
把102400改小一点试试，我是改小之后就解决这个问题了