PROCESSOR-SDK-AM62X: keywriter with SD card

Hmaied BA

Prodigy 80 points

Part Number: PROCESSOR-SDK-AM62X

Tool/software:

Hello,

I'm working on secure boot with the SK-AM62X and I have a few questions about the keywriter:

Is it possible to boot from the keywriter (kw-tiboot3.bin) on an SD card (backup boot mode)? In the AM62X_OTP_Keywriter_User_Guide, it mentions that the keywriter application has only been validated with UART, OSPI and USB-DFU boot modes.
Is it necessary to use the flashwriter to flash the regular tiboot3.bin? After writing the keys, can I boot a signed firmware from the SD card and flash the eMMC (primary boot media) from the SD?

Thank you in advance for your help!

9 months ago

0 Prashant Shivhare 9 months ago

TI__Guru 73391 points

Hello,

1. The keywriter is a SBL application so it can be booted over any ROM supported boot media.

e2e.ti.com/.../am6442-security-keywriter-not-validated-with-emmc-boot-source

2. It is not necessary. You may design your flashing procedure according to your requirements.

Regards,

Prashant

0 Hmaied BA 9 months ago in reply to Prashant Shivhare

Prodigy 80 points

Is there a way to have both the keywriter and the signed firmware on the same SD card : First, the keywriter would program the keys, and after the POR, the board would boot into the signed firmware. (The ROM always boot with the tiboot3.bin file)

0 Prashant Shivhare 9 months ago in reply to Hmaied BA

TI__Guru 73391 points

Hmaied BA said:
Is there a way to have both the keywriter and the signed firmware on the same SD card

That is not possible. You would have to manually replace the keywriter with your signed firmware after the conversion.

You may flash the eMMC with the signed firmwares in advance & then boot the keywriter firmware over other interface like SD card.

0 Prashant Shivhare 9 months ago in reply to Prashant Shivhare

TI__Guru 73391 points

Prashant Shivhare said:
You may flash the eMMC with the signed firmwares in advance & then boot the keywriter firmware over other interface like SD card.

Note: This will not work if eMMC is the primary bootmedia as the ROM would accept the signed firmware even though it won't boot.

0 Hmaied BA 9 months ago in reply to Prashant Shivhare

Prodigy 80 points

I Have

I rebuilt the keywriter and removed the key writing part (I have a GP device). Then, I copied the tiboot3.bin file to the SD card, but I don't see any logs on the M4 or R5 UART log. I also tried to build the SDK hello_world example, but I couldn't find a way to run it from the SD card.

0 Prashant Shivhare 9 months ago in reply to Hmaied BA

TI__Guru 73391 points

Hmaied BA said:
I rebuilt the keywriter and removed the key writing part (I have a GP device).

The Keywriter binary cannot boot on any device type except HSFS.

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PROCESSOR-SDK-AM62X: keywriter with SD card