Steps for Multiboot support of Single and Multi-SDCards Partitioning and Image Flashing automatically

Precondition for used SD Card

All the SD cards should be fully formatted. Use Disk tool to cleanup SD card data. Ignore Precondition steps if SD Card is fresh and empty 

Also, this method can be followed for single card multi boot flashing as well 

Note: These steps are not required for brand new SD card and you can skip

Deletion of partition using Disk tool in Ubuntu:

1) Select particular SD card from left hand side panel and click on '-' symbol of Disk tool

2) Click on Delete button to delete any particular partition

3) Finally deleted all the partitions:

Prerequisite Steps -  Preparing for flashing SD Cards

1) Keep all the below files in same location:

       i) Broadband image to be flashed

      ii) Video image to be flashed

     iii) extract.sh script file

     iv) multiSDcard_partition.sh

      v) threadSD.sh

     vi) Create a file (For ex. sudo vi sd_part_size) where all the SD card partition names and their respective sizes are mentioned

2) Connect all the SD cards with host PC and execute the command : sudo fdisk -l  . It will list all the SD card partitions with their respective sizes

3) Write all the partition names and their respective size in a text file (as created earlier as sd_part_size). Please don't copy the colon(: ) displayed at the end of the partition name and the word "GB"

For example content of sd_part_size looks like:

[Here we have taken 1 SD card of 16GB and 3 others of 32GB each.]

4) Execute the script below:   

bash multiSDcard_partition.sh <Broadband image> <Video image> <SD card details_filename>

For example:
bash multiSDcard_partition.sh rdkb-generic-broadband-image_default_20191009085525.rootfs.rpi-sdimg rdk-generic-hybrid-refapp-thunder-  image_default_20190924125426.rootfs.rpi-sdimg sd_part_size

5) Once script execution gets over pull out each SD card and verify the multiboot feature on each of them, it should be working fine as expected (Refer to Switching to RDK-Video Image from RDK-Broadband section for steps). Each SD card will boot up with Broadband image and from there executing the script bank_video_switch.sh it can be moved to the Video image(which is per-stored in the extended partition of SD card) boot up. Each SD card will contain 4 partitions.

Note: Have tested with 4 SD cards out of which 1 is 16Gb and rest of the 3 cards are 32GB each. Overall process took approximately 6min  time to get completed. Host PC having 8GB RAM. 

           For Broad band image size around 300 MB and video image (thunder) size around 700 MB

           SD card size mentioned in input text file should always be in GB but with format as provided in the steps mentioned