RE: Keep BLE Connection alive during a DFU

nordicator_prim3 — Thu, 03 Aug 2023 18:01:20 GMT

Hello,

(I'm not with nordic just a random dude). I've run into similar problems and I don't see a good way to hook into the smp code without changing it, but there may be something I'm missing!

It would be ideal if your device wasn't always in "DFU mode"; is there a button press or a bluetooth command you could send to it that would tell it to be in "DFU mode"? That would give you a way to know to expect that longer duration transmission and it would also prevent random people from putting firmware on the device when you didn't intend them to.

The way I've handled it in the past is to advertise on a different GATT/attributes than the smp server one for my main application. The application can then parse ocmmands sent to it over bluetooth from an app or computer or something. When I do want to upgrade the firmware I send a command to it that says to stop advertising the application GATT and to start advertising the way smp server expects. Then you would have a hook that would let the bluetooth stay on long enough to complete the transaction.