I think there were a few other cases that had a problem using external flash for littlefs, but I think I found out why it is not working in the latest SDK.
I configured all of the parameters for Partition manager, but the littlefs partition was always getting assigned to internal memory.
The problem is the pm.yml.file_system file does not contain a region: parameter and thus defaults to the internal flash.
I manually added "region: external_flash" and now it is working as expected, but this should be parameterized so that the user can configure the region from the application.
Could you please check and fix in the next release?
Here is the modified pm.yml.file_system file:
#include <autoconf.h>
#ifdef CONFIG_FILE_SYSTEM_LITTLEFS
littlefs_storage:
region: external_flash
placement: {before: [end]}
size: CONFIG_PM_PARTITION_SIZE_LITTLEFS
#endif
