4/27/2012

Motorola Droid Bionic Recovery



http://forum.xda-developers.com/showthread.php?t=1255888&highlight=recovery

If you've got a Droid Bionic and need to get to install a stock rom or go to recovery there are some basic steps:

Hold both volume buttons while pressing power on

This allows you to either install stock roms or go to recovery to apply updates.

Press both volume buttons in recovery to get a menu

Using systemd in Fedora

Systemd for Fedora

Systemd has been the standard "init" process on Fedora since Fedora 15. As it is compatible with SysV init scripts, LSB and chkconfig headers, it can seamlessly replace other "init" daemons like Upstart and Sysvinit.

Advantages:

  • On-demand bus activation of services
  • Aggressive parallelization of socket services
  • Support for Linux cgroups for managing process resources
  • Able to mount/unmount/automount filesystems
  • Capable of starting services based upon time
  • Elaborate transactional dependencies between services

Disadvantages:

  • Requires understanding new concepts
  • Requires learning a new configuration syntax for startup scripts
  • Not entirely compatible with all init, telinit, or service commands
  • Requires new method for taking the system to different runlevels  


Ultimately, systemd should provide you with a smoother, faster, and more efficient start up of your system. With capabilities like automounting and scheduling execution, it may even end up replacing more daemons than just init. Hopefully, by the end of this post, you will have a better idea of how to cope with the disadvantages of systemd.

If you've been using Fedora since 15 came out, then you've already been using systemd. You might not know it, until that day comes when you need to do something like rescue an unbootable system. Instead of simply passing a number representing a runlevel to the kernel, systemd uses a kernel parameter called systemd.unit.

Units

A systemd unit can be of several different types: service, socket, device, special, and target. Targets are used to group the other types of units into something similar to a runlevel. As an example, for CUPS to work there  is the cups.service, cups.socket, and the cups.path.

Targets

There are a number of predefined targets that can boot the system into different modes. Most desktop users who will want the a graphical user interface will want to use graphical.target. For systems like servers without the need for a GUI will want to use multi-user.target.


Setting The Default Runlevel

To set the default runlevel, remove the existing link in the /etc/systemd/system directory to default.target. Then, create a new link to one of the targets like multi-user.rarget or graphical.target in the /lib/systemd/system directory:
rm -f /etc/systemd/system/default.target
ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target


Changing Runlevels While Booting

In order to get to the equivalent of rescue mode, append the kernel with systemd.unit=rescue.target.
To only start up an emergency shell add the kernel parameter systemd.unit=emergency.target.
To get a non-graphical networked mode, use the kernel parameter systemd.unit=multi-user.target.
If X is installed, force the GUI mode with the kernel parameter systemd.unit=graphical.target


Changing Runlevels While Running

To do a poweroff or halt command, or like init 0, use: systemctl poweroff
The equivalent of init 3 is: systemctl isolate multi-user.target
The equivalent of init 5 is: systemctl isolate graphical.target
To do a reboot or init 6, use: systemctl reboot

Managing Services

Like service httpd start is systemctl start httpd.service 
Like service httpd stop is systemctl stop httpd.service
Like service httpd status is systemctl status httpd.service
Like service --status-all is systemctl --all or systemctl -a


Enabling/Disabling Services

If you are a Debian/Ubuntu user, then instead of checkconfig you may be using:
sudo update-rc.d apache2 enable 
sudo update-rc.d apache2 disable

If you are using Fedora:
Like chkconfig httpd on is systemctl enable httpd
Like chkconfig httpd off is systemctl disable httpd

Units can also be disabled by masking them, and this can prevent a unit from becoming enabled automatically:
Like chkconfig cups off is systemctl mask cups

A masked unit can be unmasked to enable the service:
Like chkconfig cups on is systemctl unmask cups

Recovery in Rescue Mode
In rescue mode, the system may not have loaded your logical volumes, particularly if there was an error on one of those volumes. Since various subcommands of lvm are not directly available, so a command like vgchange -ay, will have to be executed as lvm vchange -ay.

In order to fix a logical volume with an error on it (which reared it's ugly head right as I was about to start a presentation at SCALE 11X), here's the process I followed:
lvm vchange -ay
lvm lvs
fsck -y /dev/vg_rocket/lv_home




About Me - WrightRocket

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I've worked with computers for over 30 years, programming, administering, using and building them from scratch.

I'm an instructor for technical computer courses, an editor and developer of training manuals, and an Android developer.