J
@toughrock Can you explain us why you don't want to save NVRAM?
The ACK flag is a LoRaWAN feature that is driven automatically by the LoRaWAN stack. When you receive a (confirmed) downlink, the next uplink will have the ACK flag set, so the network knows the downlink has been received and it can send the next one (otherwise it will send the same downlink again).
If the network and/or network API and/or server support it, you could simply set the downlink as UNCONFIRMED and you would not need the ACK to be set.
But going to deep sleep without saving the LoRaWAN state will result in a lot more issues than just a missing ACK flag:
Frame counters will be reset
You would have to re-join each time, which is time-consuming
Other MAC commands would have no effect, such as channel list updates, ADR, etc.
So, what's your issue with saving the LoRaWAN state?