There are a couple of options available for this, you can either remove the requirement to login completely or change the password for 'root' access.
# disaster recovery if necessary
::wait:/etc_ro_fs/init.d/sysinit
# system initialisation
::wait:/etc_ro_fs/init.d/rc.sysinit
# bash
::askfirst:-/bin/login
#::askfirst:-/bin/sh --login
to
# disaster recovery if necessary
::wait:/etc_ro_fs/init.d/sysinit
# system initialisation
::wait:/etc_ro_fs/init.d/rc.sysinit
# bash
#::askfirst:-/bin/login
::askfirst:-/bin/sh --login
root:$1$pYf7MyKG$pVYskWhG47zMmpoBBJGM10:0:0:root:/root:/bin/sh
to
root::0:0:root:/root:/bin/sh
This will allow you to login at a command prompt without needing to know the password. Once you have logged in
you can create a password for the 'root' account by typing 'passwd' and following the prompts (assuming that busybox has the passwd applet
enabled). This will create a new password for 'root' that you would need to enter in order to login.