Create External Flash Partition for nRF5340 in Thingy:91x is failed

[Billy Wan]

I want to use the nRF5340 in Thingy:91x to control the external flash (256M bit) and pariition it as LittleFS. I can be sucessfully create partition in nRF5340DK but cancan achieve in Thingy:91x. I tried many ways to modify the pm_static.yml and thing91x_nrf5340 board overlay and cannot acheive it. I want some example so that I know how to create partitiion of the external flash for nRF5340 in Thingy:91x. Please help. Thanks.

[Amanda Hsieh]

Hi Billy, 

What NCS version are you using?

For v3.4.0, You can check out the thingy91x_nrf5340_cpuapp.overlay in https://github.com/nrfconnect/sdk-nrf/blob/v3.4.0/samples/wifi/shell:

https://github.com/nrfconnect/sdk-nrf/blob/v3.4.0/samples/wifi/shell/boards/thingy91x_nrf5340_cpuapp.overlay

https://github.com/nrfconnect/sdk-nrf/blob/v3.4.0/samples/wifi/shell/sysbuild/mcuboot/boards/thingy91x_nrf5340_cpuapp.overlay 

https://github.com/nrfconnect/sdk-nrf/blob/v3.4.0/samples/wifi/shell/sysbuild/b0/boards/thingy91x_nrf5340_cpuapp.overlay 

Regards,
Amanda H.

[Billy Wan]

Hi Amanda, thank you for your support. I had tried the examples you provided in V3.4.0. I can create a partition in external flash. However, I cannot using the partition in external flash as LittleFS partition. When I mount it as LittleFS partition, it always have <err> test: FAIL: unable to find flash area 0: -2 and <err> test: Mount LittleFS Error -2. Could you provide the example showing how to define LittleFS partition for external flash for nRF5340 in Thingy:91x by using Sysbuild in ncs V3.4.0. Thanks.

[Amanda Hsieh]

The error FAIL: unable to find flash area 0: -2 (where -2 corresponds to -ENOENT / file or entry not found) occurs when Zephyr cannot locate the flash partition or flash area ID at runtime

There is no dedicated sample demonstrating a LittleFS partition for external flash for nRF5340 in Thingy:91x, but you can refer to nrf52840dk_nrf52840_spi.conf and nrf52840dk_nrf52840_spi.overlay. 

The Wi-Fi shell overlays you referenced define MCUboot secondary slots on external flash (image-1, image-3). They do not define a LittleFS partition, and they do not wire up a filesystem mount.

[Billy Wan]

Hi Amada, I found out that the error was caused by nRF9151 in Thingy:91x, which used SPI and external flash as well. When I erase the program for nRF9151, nRF5340 can access the external flash as LittleFS. The current issue is how to make the MCUBoot in nRF9151 not to use external flash. I tried but not sucessful. The default sysbuild for nRF9151 in Thingy:91x is need to put MCUBoot in external flash. Any example which showed how to make nRF9151 only use internal flash for MCUBoot and not to use external flash anymore?