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TMS320C5515: What is Bootloader reauthoring?

Tony Tang
Mastermind 29902 points

Part Number: TMS320C5515

What is mean of Bootloader reauthoring? to my understanding, bootloader read flash only. when and how booloader writing booting device/flash?

2.2.1 NOR Flash
The bootloader supports booting from a NOR Flash attached to any of the four external memory interface
(EMIF) chip-selects. The NOR Flash must use a 16-bit data bus.
Any 16-bit NOR Flash device should work for read-only use. To support bootloader reauthoring, which
requires writing to the device, CFI-compliant bottom-boot-block and uniform-boot-block devices should
work. Top-boot-block devices may or may not work (vendor dependent due to non-standard CFI
implementations).
The following is a list of NOR Flash devices that are explicitly supported for reauthoring (writing). Other
devices may be supported.
• Spansion S29GL016A
• Spansion S29AL016M
• MXIC MX29LV160T
• Spansion S29GL032A
• SST SST39LF/VF200A
• SST SST39LF/VF400A
• SST SST39LF/VF800A

  • 0
    TI__Guru**** 161600 points
    Hi Tony,

    I've notified the C5000 team. Their feedback will be posted here.

    Best Regards,
    Yordan
  • 0
    TI__Mastermind 30250 points

    Hi Tony,

    The bootloader is capable of supporting 2 different encrypted boots (but we do not support these for catalog customers):
    1) encrypt the image and decrypt it with the bootloader - encrypted image is identical in non-volatile memory from board to board
    2) encrypt the image and make it unique from board to board by re-authoring the encrypted image with a second chip-specific encryption seed. On the very first boot with re-authoring (#2) selected, the bootloader re-encrypts the image and writes it back to the non-volatile memory so that the encrypted image on board A is different to the encrypted image on board B and every other board. This makes it more difficult to reverse engineer the bootloader image. Still, the encryption used is not as strong as more modern encrypted boot-loaders. This is one reason we don't support it.

    Hope this helps,
    Mark