Hey,
We are trying to enable encryption on our images. Therefore, we need to generate the DEK blob during our manufacturing process so the MCU's have the required key to decrypt the images later.
On my desk setup I managed to generate the DEK blob for a device using the sdphost and spsdk blhost commands, while being connected to the LPUART1 peripheral of the MCU.
The commands I used:
1) sdphost -p ... -j -t 110000 -- write-file 0x20001C00 MIMXRT1060_flashloader.bin
2) sdphost -p ... -j -- jump-address 0x20001C00
3) spsdk blhost --port ... generate-key-blob --key aes_key.bin --output dek_blob.bin
The problem is that our LPUART1 is not exposed on our final PCB. The LPUART1 is connected to RS485 half duplix. The LPUART3 however is available and could be used but the flashloader application does not support this.
We also don't have the USB peripheral available on our PCB.
My question is, how can we retrieve the DEK blob.
Can we create a custom flashloader application which uses LPUART3?
Can we call a special function within the IMXRT to generate this DEK blob? This function could then be integrated into our software.
Looking forward to hearing from you.
Kind regards,
Maxim
