stuck in a login loop

[guiyii]

Hey guys, I have Arch Linux ARM running on a raspberry pi. One night, I plugged in a wifi dongle, the system somehow got shut down. I suspected that the dongle was drawing too much power. After I rebooted the system, I found out that the ethernet was disabled. I managed to get the ethernet to work again, and left operating system as it was.

However, the second day when I tried to start the operation system, it was stuck in a login loop -- after I type in the username and the password, the screen flashes a few lines of messages and prompts me to log in again.

I managed to snap a picture of the flashing screen, and I have it transcribed here:
$this->bbcode_second_pass_quote('', '
')Arch Linux 3.6.11-11-ARCH+ (tty1)

moripi login: root
Password:
Last login: Thu Jan 1 01:10:44 BST 1970 on tty1
Last login: Thu Jan 1 01:12:37 on tty1
-zsh: error while loading shared libraries: libncursesw.so.5: cannot open shared object file: No such file or directory

[WarheadsSE]

Immediately, you could go single-mode, or just pop the card into another machine and edit the the user to use bash instead of zsh, since it seems to be what is crapping out. It needs an update.

[guiyii]

How do I go single-mode? I assume that means single-user mode?
Also, for the second option, do I insert the SD card into another raspberry pi? That doesn't seem to work for me...

[WarheadsSE]

Insert it into anything that runs linux, and edit the file /etc/passwd and change your shell.

[guiyii]

...OK. I don't have any machine handy that takes SD cards at the moment. What if I choose the first option:
$this->bbcode_second_pass_quote('WarheadsSE', 'I')mmediately, you could go single-mode

[WarheadsSE]

The kernel command line parameters are controlled by commandline.txt on the first partition of the Pi. You will need to edit that file.

[guiyii]

Thank you! I really appreciate your responses so far, and I hope you could still bear with me a bit longer...
When booting up, I held "shift" to enter the recovery mode, and added "1" at the end of the cmdline.txt? Is that how I am supposed to enter single user mode?

When it finished booting, It prompts $this->bbcode_second_pass_code('', '
Welcome to the rescue mode! Type "systemctl default" or ^D to enter default mode
Type "journalctl -xb" to view system logs. Type "systemctl reboot" to reboot.
Give root password for maintenance
(or type Control-D to continue):')
I tried pressing Control-D and entering the root password. Both directed me to the same login loop I was trapped in before.
So I wonder what I have done wrong here.