NOTE: Please first read the following: http://files.dune-hd.com/sdk/doc/html/dune_devel_info.html Boot process involves the following steps: 1. Boot loader from serial flash in Sigma Designs SMP86xx chip. 2. Boot loader from NAND flash. 3. Linux kernel from NAND flash. 4. /sbin/init and /etc/init.d/rcS 5. /etc/init.d/S99local 6. /tango/bdstart.sh 7. /tango/firmware/bin/root 8. /tango/firmware/bin/shell NOTE: - Steps 1-5 are handled by the hardware, boot loader and Linux kernel. - Steps 6-7 are handled by the code residing in /tango partition. More details: - /etc/init.d/S99local - This is the main boot script residing in the rootfs filesystem (which is the part of the Linux kernel image). - This boot script performs the following steps: - Loads various drivers: - FIP (front interface panel) driver. - IR (remote control) driver. - Drivers for storage devices (SATA, USB, SD card). - Drivers for additional filesystems (e.g. NTFS). - NAND flash driver. - Checks for local storage devices (e.g. USB flash drive). - If such devices are found, they are tried to be mounted. - NOTE: All mounted local storage devices are kept mounted in /tmp/boot_mnt/; these temporary mounts points are called "boot mounts"; at a later boot stage, /tango/bdstart.sh script will further analyze them and remount them into an appropriate final location. - Checks if emergency firmware recovery should be performed (triggered by "dune_firmware.dff" file in the root of any mounted local storage device). - Emergency firmware recovery updates all parts of the flash memory which are updated during normal firmware upgrade process. This includes all read-only parts of the firmware, such as Linux kernel and /tango. This does not include /mnt flash memory parition which is used to store STB settings. - After emergency firmware recovery is finished, the STB hangs and the user should remove the local storage device with "dune_firmware.dff" file and manually reboot the STB. - Checks if emergency settings reset should be performed (triggered by "dune_boot_reset_settings.flag" file in the root of any mounted local storage device). - Emergency settings reset reformats /mnt flash memory partition which is used to store STB settings. - After emergency settings reset is finished, the STB continues normal boot process. - Mounts the main read-only flash memory partition to /tango. - Mounts the main read-write flash memory partition to /mnt. - If this fails (e.g. the filesystem is corrupted), reformats it and retries. - Calls /tango/bdstart.sh. - /tango/bdstart.sh - This is the main boot script residing in the /tango partition. - This boot script performs the following steps: - Loads some additional drivers. - Does some additional initialization. - Prepares some symlinks. - Prepares some environment variables. - Prepares some required directories and files in the RAM disk (e.g. in /tmp). - Handles "boot mounts", remounts some of the local storage devices to /persistfs ("system storage") and /D ("main storage") when needed. - Loads Sigma Designs MRUA drivers (microcodes and kernel modules). - Frees resources occupied by the boot splash. - Mounts /firmware_opt and/or /flashdata flash memory partitions, when they exist. - NOTE: The following scripts are used here: - /tango/firmware/mount_firmware_opt.sh - /tango/firmware/mount_flashdata.sh - Does some more initialization. In particular, calls the following extra init scripts: - /tango/firmware/scripts/init_timezone.sh - /tango/firmware/scripts/init_cron_apps.sh - /tango/firmware/ftpserver/run - /tango/firmware/smbserver/run - /tango/firmware/scripts/init_ssh_server.sh - Calls the following script, if it exists (can be used in custom firmware builds to do some extra custom initialization on STB boot): - /tango/firmware/config/start.sh - Does some more initialization. - Finally, launches the following executable: /tango/firmware/bin/root - /tango/firmware/bin/root - This is the main executable which is launched in the end of the boot process. - This executable does the following: - Initializes certain aspects of STB hardware according to STB settings. - Prepares various system stuff (in particular, creates various important files in /tmp filesystem). - Launches all executables from /config/boot/ directory (if any). - NOTE: executables are launched sequentially and synchronously. - Launches various background activities and processes, in particular: - /tango/firmware/scripts/init_network.sh - /usr/sbin/httpd - /tango/firmware/bin/storage_manager - NOTE: applicable for firmware versions ..._b7+. - Checks if "emergency eject on boot" procedure should be performed (triggered by pressing "EJECT" button on the remote control) (useful for preventing an attempt to read an optical disc in the optical disc drive). - Finally, launches /tango/firmware/bin/shell in a loop (whenever shell is terminated, it is automatically restarted).