Partition Table Reference

The exact contents of partitions.csv for the 16 MB ESP32-S3-N16R8. The reasoning behind every entry: flash partitions.

Name	Type	SubType	Offset	Size	Holds
nvs	data	nvs	0x9000	64 KB	Settings, favorites, cards, schedules, resume record, API token
phy_init	data	phy	0x19000	4 KB	Radio calibration data
otadata	data	ota	0x1A000	8 KB	Boot slot selection, two redundant copies
ota_0	app	ota_0	0x20000	4.5 MB	OTA slot A (USB flashes land here)
ota_1	app	ota_1	0x4A0000	4.5 MB	OTA slot B
storage	data	littlefs (0x82)	0x920000	2 MB	Dashboard files, TLS certificate and key
coredump	data	coredump	0xB20000	64 KB	Crash post-mortems
nvs_key	data	nvs_keys	0xB30000	4 KB	NVS encryption key material (production)

Production builds use partitions_production.csv instead of this table: it sits at offset 0x10000 (Secure Boot V2 bootloader headroom) and moves nvs_key to 0xB50000. The 0xB30000 row above, including its (production) annotation, is the development and legacy layout.

There is deliberately no factory partition: A/B OTA never rewrites it, so it only wasted 3 MB. With otadata blank the bootloader logs "No factory image, trying OTA 0" and boots ota_0; a failed OTA falls back to the other slot. All data partitions keep the offsets of the previous table, so encrypted NVS and the dashboard image survive the upgrade; the one-time move from the three-slot layout requires a full USB flash.

Flash offsets used when writing a full image over USB (always include ota_data_initial.bin so a stale slot selection cannot point at an empty partition):

python -m esptool --chip esp32s3 write_flash \
  0x0      bootloader.bin \
  0x8000   partition-table.bin \
  0x1a000  ota_data_initial.bin \
  0x20000  Safi.bin \
  0x920000 storage.bin

Rules for edits (alignment, immovable entries, the full-flash requirement after changes) are in the partitions chapter.