Tizen 4.0 comes with 3 different root filesystems, each designed for a different purpose.
Table: Root filesystems
|Main root filesystem
|Regular boot ramdisk
|System recovery ramdisk
This topic describes operation and customization options of the system recovery ramdisk.
The following steps describe the boot process:
The boot process starts with a bootloader (u-boot or s-boot) loading appropriate kernel and ramdisk images dedicated for the system recovery process (methods for controlling bootloader actions are beyond the scope of this document). With both images loaded into RAM, the kernel initialization begins. When the initialization is complete, the kernel passes control to the init process, such as
In the case of the recovery ramdisk,
/sbin/initis a symlink to
/usr/libexec/initrd-recovery/init(a shell script that comes from the
initrd-recoverypackage). The script mounts several kernel filesystems and the inform partition (if it exists), and parses the kernel command line options (
/proc/cmdline) to find the
bootmodeparameter. If the parameter is present, one of the
/sbin/*-initscripts is started. If the boot mode is set to
recovery-initscript mounts the real root filesystem under the
/systemdirectory, and other filesystems (such as
/opt/usr) below the
/systemdirectory. The script starts a shell on the serial console and launches the
system-recoveryprogram searches the removable storage for
tizen-recovery.imgwhich has the compressed partition image and config file. The
tizen-recovery.img, and dumps the partition image to the appropriate block as mentioned in the config file.
Adding new files to the
ramdisk-recovery partition is created along with the
partition (methods for creating images are beyond the scope of this
- Files to be added to the
ramdisk-recoverypartition must be available in Tizen RPM packages.
- Files are added to the partition by the
mkinitrd-recovery.shscript, which is started automatically as a part of the
%posttransRPM script of the
To install a selected file in the recovery
image, its RPM needs to be installed before
initrd-recovery is run. The
easiest way to make sure this happens is to list the package as a
dependency in the
mkinitrd-recovery.sh script copies or moves files from the
rootfs partition to the
initrd-recovery partition according to
directions provided in configuration files stored in the
/usr/share/initrd-recovery/initrd.list.d directory. These files
must be packaged in the RPM packages together with the
files to be put on the
initrd-recovery partition. The configuration files are
interpreted as shell scripts and can be used to set the following
DIRECTORIES: Create directories.
DIR_SYMLINKS: Create symbolic links to directories.
LIBONLYS: Copy only the libraries required by the listed executable files.
MVWITHLIBS: Move the listed executable files and copy the required libraries.
SYMLINKS: Create symbolic links.
VERBATIMS: Copy the listed files. List non-executable files here.
WITHLIBS: Copy the listed executable files and the required libraries.
DIR_SYMLINKS variables contain pairs of filenames separated with
The following section contains examples of the above variables:
The following real-world example comes from the
package. Following this configuration,
some basic tools to the
initrd-recovery partition, moves
minireboot, and creates some symlinks: