Updating the Root Filesystem and Kernel

The camera board has the U-Boot bootloader installed, which normally boots into Linux on startup. However, we can interrupt the normal boot sequence and enter the U-Boot shell. Within a few seconds after the board has been turned on, hit any key at the "Hit any key to stop autoboot" prompt. From here we can update the kernel and root filesystem. The kernel and root filesystem images are located in citric/image.

Updating the Linux Kernel

  1. At the command prompt, enter run kernel
  2. Send zImage02_lcd_backlight_disable using the Kermit protocol
  3. When the process is done receiving and erasing/copying sectors, it will return to the U-Boot prompt. Type boot to boot the camera board.

Updating the Root Filesystem

  1. At the command prompt, enter run rootfs
  2. Send rootfs.cramfs using the Kermit protocol
  3. When the process is done receiving and erasing/copying sectors, it will return to the U-Boot prompt. Type boot to boot the camera board.

Modifying the Root Filesystem

The root filesystem contains a few files/directories of interest:

Compressing the Root Filesystem

The root directory (citric/rootfs) must be compressed into a cramfs image. This can be done with the application mkcramfs (/sbin/mkfs.cramfs on Fedora distributions).