SB and SFU

[Vmere.1]

Hey guys,

I want to perform a firmware upgrade over the air. And use a UART to connect to IoT device.

I use stm32l431xx and it contains hardware for symmetric encryption. And the host device which sends the binary uses stm32l496 has SBSFU.

So I have a constraint now, I don't want to make many changes to the bootloader apart from boot entry points logic. I want to use only the SFU package in SBSFU. Is this possible?

Regards,

Vmere.

[Bubbles]

Hi @Vmere.1​,

I'm not sure to understand your case. Is that the stm32l496 is sending encrypted firmware package to the stm32l434 using UART? That's probably no issue right?

And then you want to unpack it on the stm32L431 without secure boot? It should be possible to adapt such scenario starting from the L432 SBSFU example. Just identify the firmware decrypting part of the SBSFU and hack the rest off.

BR,

J