So a 410K image needs a 1MB flash assuming SPIFFS is not using flash. With larger flash you can choose how much to allocate to program and how much to SPIFFS. So a 4MB could be allocated at 1MB program and 3MB SPIFFS. A 2/2 or 3/1 split allow for larger program images with OTA although maximum image size is 1M anyway.
So a 410K image needs a 1MB flash assuming SPIFFS is not using flash. With larger flash you can choose how much to allocate to program and how much to SPIFFS. So a 4MB could be allocated at 1MB program and 3MB SPIFFS. A 2/2 or 3/1 split allow for larger program images with OTA although maximum image size is 1M anyway.