# Flash partition layout

The N16R8 target has 16 MiB flash and 8 MiB octal PSRAM. PlatformIO uses the custom [`partitions.csv`](../../partitions.csv) layout:

| Partition | Offset | Size | Purpose |
|---|---:|---:|---|
| `nvs` | `0x009000` | 512 KiB | Serial, Wi-Fi, mDNS hostname, local-display, role-based user, HTTPS identity, and SSH host-key data |
| `otadata` | `0x089000` | 8 KiB | Active OTA-slot selection metadata |
| `phy_init` | `0x08B000` | 4 KiB | Optional PHY initialization data |
| `nvs_key` | `0x08C000` | 4 KiB | Reserved for future encrypted-NVS keys |
| `coredump` | `0x08D000` | 128 KiB | Reserved for flash core dumps |
| `ota_0` | `0x0B0000` | 4 MiB | Primary application/OTA slot |
| `ota_1` | `0x4B0000` | 4 MiB | Alternate application/OTA slot |
| `storage` | `0x8B0000` | 7488 KiB | Reserved; not mounted or used for session recording |

Application offsets are aligned to the ESP32-S3's required 64 KiB boundary. The final storage partition ends at `0x1000000`, exactly the end of the 16 MiB flash chip.

Admin HTTPS application upload uses the inactive OTA slot and `otadata`; NVS and other data partitions are untouched by the updater. It does not provide remote downloads, automatic rollback/health confirmation, core-dump handling, NVS encryption or filesystem mounting. Image validation does not guarantee a working application; compatible storage schemas and wired recovery remain the owner's responsibility.

Partition reservations do not enable their named features. In particular, `nvs_key` does not enable encryption, and the default firmware does not capture core dumps. Existing generated SDK configurations can override `sdkconfig.defaults`; inspect the effective configuration when verifying a build's security properties.

See [first installation and destructive migration](../getting_started.md#partition-migration-and-erasing) and the [firmware update guide](../firmware_update.md) for operator procedures. Do not change partition offsets as part of an ordinary application update.