CC3235S: OTA mcuimg.bin without signature

Tomas Malmelöv

Part Number: CC3235S
Other Parts Discussed in Thread: CC3220R, , CC3220S, CC3230S, CC3200

Hi,

Im wondering if it's possible to update /sys/mcuimg.bin in some way without using signature, just as an unsecure file. It's created as below in the image.syscfg file, however is ther any way to add a flag like SL_FS_CREATE_NOSIGNATURE to make this possible.

The reason to do this is that I want to do OTA without using any cert and signatures, which was possible when working on the CC3220R product

Thanks,

/TM

over 1 year ago

0 RogelioD over 1 year ago

TI__Genius 9475 points

Hello Tomas.

So the short answer is No. The CC3235S requires an image signature to verify the integrity of the image. This security was added to the CC3220S,CC3230S, and CC3235S. I refer you to the table 8-4 in the CC3x3x Network Processor User Guide.

However, you could bypass Root CA certifications between the device and the server. I will note that this is not recommended but more information can be found in section 4 of CC3x3x OTA Update.

Hope this helps,

Rogelio

0 Tomas Malmelöv over 1 year ago in reply to RogelioD

Prodigy 155 points

Hello,

Ok, I can add that Im using an OTA implementation for GEN 1 devices, cc3200, it has worked good for cc3220R but getting stuck now when moving to S device. So I guess that OTA_SERVER_ROOT_CA_CERT, if that's what you are talking about, doesn't help here..

So only option is to send a signature together with a new mcuimg.bin and use that for the FsClose execution?

+1 RogelioD over 1 year ago in reply to Tomas Malmelöv

TI__Genius 9475 points

Correct. Since the cc3235S now requires the mcuimg.bin file to be secured you will need to have the signature to be able to write to it. Once the file is properly closed and was not aborted in the process then your new image will commit, if not the fail safe will rollback to the original file.

For help creating a signature I would read section 8.4.7 in the CC3x3x Network Processor User Guide as well as the OTA example on the simple link academy Wi-Fi OTA

Best Regards,

Rogelio

0 Tomas Malmelöv over 1 year ago in reply to RogelioD

Prodigy 155 points

Yes, works fine when providing the signature together with the .bin file. Thanks for helping me!

Wi-Fi

Wi-Fi forum

CC3235S: OTA mcuimg.bin without signature