Using LoRaWAN and deepsleep

[tuftec]

I have been able to get my LoPy4 working successfully using both LoRa and Sigfox.
I have now started to use deepsleep (unit sleeps for several minutes between transmissions).

I can get Sigfox to work after waking from deepsleep but can not get LoRa to work.
I am trying to use lora.save() and lora.restore to recover the connection parameters so that I do not have to rejoin each time after wake. But I just can not get it to work.

Can someone please help with a code example that I can use as a guide.
I am using OTAA activation initially. The OTAA connection appears to work but I just can not send data after waking from deepsleep and recovering the original parameters from nvram.

Thanks

Peter.