Hello,
I'm looking for answers and some explanation for two main questions - is it possible to perform non-simultaneous multi-image FOTA over WiFi? Is it possible to support update rollback for both cores on the nRF5340?
For context, I'm currently working with a custom board that features the nRF5340 (running custom application on application core, HCI IPC sample on network core), nRF7002, and external SPI-NOR flash (where all new images are being stored and swapped). The company I work for maintains a private server from which images are downloaded via HTTPS, and we're looking to support rollback functionality for at least the application core, but ideally for the network core, as well.
I've seen some threads, such as this one, that suggest that this capability is not supported at all due to the reason mentioned in the documentation for simultaneous multi-image updates. Additionally, in taking the complete DevAcademy NCS Intermediate course (being sure to read through the DFU lessons multiple times), I saw it mentioned why non-simultaneous updates are discouraged for the nRF5340.
So, if simultaneous multi-image updates prevent rollback capability, and the usage of BLE for DFU prevents non-simultaneous updates from being feasible for the nRF5340, I feel the resultant predicament begs the question, wouldn't a non-simultaneous multi-image update work fine in my use case? Since the network core is only running the HCI IPC sample and DFU is taking place over WiFi via the nRF7002, in the event that the interface between the cores changes, the host MCU would still be able to download and apply the network core's update despite not being able to communicate with it, right? Or are there other interactions between the cores that are necessary for the host's operation and would prevent it from updating the network core?
I'm not seeing much more documentation on the topic of non-simultaneous multi-image updates other than them not being recommended for FOTA, so I can't tell if this is a lost cause, but if they are feasible, then wouldn't update rollbacks for either core also be feasible?
Thank you!