MODE=/usr/sbin/chroot /mnt/initfs cal-tool --get-rd-mode

to be

MODE=enabled #/usr/sbin/chroot /mnt/initfs cal-tool --get-rd-mode

You can use vi editor for this, enter

vi /usr/sbin/gainroot 

position cursor at '=' character, press 'a' key, enter 'enabled #', press Esc key and save and exit with 'ZZ' command (shift + zz). The edited line may look garbled but it is OK. CTRL+L refreshes screen in vi so you can double check before saving.

From now you can use the intended way how to gain root on the device in R&D mode without having to set it.

$ sudo gainroot

Set user password

Set the password for 'user':

passwd user

Note: when typing a password nothing will be shown on the screen.

Now, for the future, unless you want to keep SSH-ing from another machine, a clever move is to add "user" to sudoers:

echo "user ALL = PASSWD: /bin/su" >> /etc/sudoers

this way your password will be asked in order to become root. Or

echo "user ALL = NOPASSWD: /bin/su" >> /etc/sudoers

in order to become root without having to type your password.

Please keep in mind that password will be cached, so you won't have to type it every time you need to sudo.

Note that if you require a password to become sudo, some built-in apps (notably Application Manager) will appear to not load while they wait silently in the background for the password to be entered. The can be avoided by running a command in the xterm with sudo prior to lauching the app, so as to appease sudo when the OS calls it.

Ok, from now on all you have to do, in your Xterm session, to get root is to write:

sudo su -

Secure the root account

You MUST change (or disable) your root password before continuing!

Else you will be walking around with a device that can be accessed using a TRIVIAL and well known password.

Change root password

To change root password (as root user):

passwd

...when asked, input (twice) your new password.

It is still recommended to limit root logins to local console only in most cases.

Disable root login (highly suggested)

NOTE: Do not perform this step without having completed Step Modify the gainroot script or Set user password

After you gained access as root user:

passwd -l root

In this case, from now on you won't be able to login directly as root user -- not from ssh and not from the local console.

To get a root prompt:

sudo su -

Disabling root login when using OpenSSH

This step is semi optional. Definitely recommended for most installations, though.

When using dropbear as ssh server, you can disable root logins via ssh: just add the option "-w" to DROPBEAR_EXTRA_ARGS in /etc/default/dropbear:

DROPBEAR_EXTRA_ARGS="-w"

After that, restart dropbear:

/etc/init.d/dropbear restart

A remote root login via ssh is then no longer possible. So you have to use the "user" account (you should give the user a password beforehand).

For Windows Users Only

Obviously the same trick works also in Windows, but you have to use a (free or commercial) SSH enabled client:

• Absolute Telnet
• SecureCRT
• PuTTY, etc...

R&D Mode

Note: As R&D mode has other side effects beyond simply enabling root access (including several that can negatively impact battery life), it is not the recommended method for gaining root access. Use easyroot instead.

You can enable the Research & Development mode (R&D or RD mode, which enables you to execute sudo gainroot to get a root shell, simply follow the setup steps for flashing covered in Upgrading tablet OS, then execute

sudo ./flasher-3.0 --enable-rd-mode -r