Based on the am335x EZSDK brought smallest file system, I had made the following changes:
this is the etc directory under.

After booting uImage, execute / etc / inittab
the inittab content here ,
#etc/inittab
::sysinit:/etc/init.d/rcS
::respawn:-/bin/sh
::ctrlaltdel:/sbin/reboot
::shutdown:/bin/umount -a -r
the result on the starter Kit board running
INIT: version 2.88 booting
INIT: /etc/inittab[2]: missing id field
INIT: /etc/inittab[3]: missing id field
INIT: /etc/inittab[4]: missing id field
INIT: /etc/inittab[5]: missing id field
PS :I check the link of the sbin/init
init -> init.sysvinit
but I am referring to Samsung's file system
the link of the /sbin/init is init->../bin/busybox
I have a try to change the link direction to the ../bin/busybox
the running reuslt :
init: applet not found
[ 2.089385] Kernel panic - not syncing: Attempted to kill init!
[ 2.095581] Backtrace:
[ 2.098175] [<c0017dbc>] (dump_backtrace+0x0/0x10c) from [<c041b5e8>] (dump_stack+0x18/0x1c)
[ 2.106994] r6:cf01bc00 r5:c04fa5fc r4:c062ef88 r3:c05e4e10
[ 2.112915] [<c041b5d0>] (dump_stack+0x0/0x1c) from [<c041b7e4>] (panic+0x64/0x194)
[ 2.120941] [<c041b780>] (panic+0x0/0x194) from [<c0041b8c>] (do_exit+0x5b0/0x65c)
[ 2.128845] r3:cf01bc00 r2:cf01df60 r1:cf01df60 r0:c04fa5fc
ps:My aim is to start the sequence is inittab -> / init.d / rcS
without judge runlevel, I guess the question is the link with the init direction of a relationship, how to solve?