nRF9160 running out of flash

[Samuel Pell]

Hi,

We are close to running out of flash on the nRF9160 (with MCUboot enable) and we still have functionality to implement for our product. There are two possible options we have thought of:

1. Reducing the size of the secure parititions and increasing the size of the secure flash partitions. How would we do this, would we have to create our own board configuration and change the device tree to change the partition sizes? Or is there some other way of changing the flash partition sizes?
2. Including an external flash chip for extra program space. Is it possible to execute a program from an external flash chip with the nRF9160? If so, are there any examples for this? If not, could we use this as the slot2_partition for firmware-over-the-air updates via MCUBoot?

Thanks

[Simonr]

Hi

One thing you could do is to use an external flash (SPI) to save app slot 2 there, and then, after DFU is finished, you can erase slot 1 on the internal flash, and write what is on the external flash (slot 2), to slot 1.

Depending on which nRFConnect SDK (NCS) version you're using, there have been some flash optimization done in modemlib in the latest NCS versions, so if you upgrade to I.E. v1.7.0, there should be more flash available for the application. 

Lastly, my colleague Håkon made an external flash DFU example for NCS v1.7.0 just last week. Please check out this case for more information on that.

Best regards,

Simon