GPIOs under DFU mode are set randomly

[WJi.2]

Hi​ ST support team,

I am using STM32L4 for a developing project. And I recently found that the GPIOs under DFU mode are set very randomly.

That means, for most of the boards we produced, for a specific pin, it is set as LOW, but some are set as HIGH.

I wonder how we could configure the GPIOs under DFU mode, or they are not configurable at all?

Thanks very much in advance :)

BR

[Tesla DeLorean]

The ROM based system loader is very general in implementation, it has zero awareness of your board design/requirements.

For board specific stuff you're expected to implement your own loader.

[WJi.2]

Hi Clive,

Thanks for your quick reply.

Basically we just need to set up a few GPIOs.

I wonder if you have a guide to implement our own loader, please?

Thanks :)