Can't login root account due to can't find root shell

Hi, yesterday, I changed root's shell in /etc/passwd, cause a mistake then I can not log in root account (can't find correct shell). I attempted to log in single-mode, however, it prompted for single-mode's password then I type root's password but still can not log in.
I'm using AIX 5L version 5.2 with machine pSeries 655.
Is there anyway to solve this problem without using a bootCD ?
Please help.

boot off a mksysb tape
boot off a NIM server

Why are you changing roots default shell?? Besides that you should use a system utility to manage accounts and not directly edit /etc/passwd.

Thank you for your help,
I'm reading about mksysb and NIM.
However, fortunately, I have another account can login, and I used "su -c 'vi /etc/passwd' " to solve my problem.
However, that's a lucky circumstance, and I going to study NIM.

Thank you very much.
Best Regards.