# Help needed for Zigbee custom partition scheme for ESP32 C6 Qwiic Pocket **URL:** \ **Category:** ESP32\ **Created:** [October 30, 2025, 10:45pm UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249 "2025-10-30T22:45:50Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![JohnLand](https://avatars.discourse-cdn.com/v4/letter/j/d2c977/32.png) [@JohnLand](https://community.sparkfun.com/u/JohnLand)\ **Post date:** [October 30, 2025, 10:45pm UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249/1 "2025-10-30T22:45:50Z")
I’ve developed a sketch that sends distance data (derived from a VL53L1X Time-of-Flight sensor) from a 4MB ESP32 C6 Qwiic Pocket (EQP) to a Hubitat hub. With a little effort (i.e., using the Double Luck Voodoo pairing process well-known to Hubitat users), the EQP pairs fine. I’ve posted my sketch and an accompanying Hubitat driver in the Hubitat community forum. Compiled, my sketch uses 54% of the program storage space; maximum is 1,310,720 bytes. I used the partition scheme “Zigbee ZCZR 4MB with spiffs”. I tried adding WiFi and OTA capability, but the libraries needed for that functionality put my sketch at 109% of the available program storage space. I tried a LOT (with the help of Claude AI) to craft a custom partition scheme that provided more program space while staying within 4MB and enabling both OTA and Zigbee, but no variant would work. Below is the last version I tried, which sent the EQP into an endless boot loop. ```auto # Name, Type, SubType, Offset, Size, Flags nvs, data, nvs, 0x9000, 0x6000, phy_init, data, phy, 0xf000, 0x1000, otadata, data, ota, 0x10000, 0x2000, app0, app, ota_0, 0x20000, 0x1A0000, app1, app, ota_1, 0x1C0000,0x1A0000, zb_storage, data, fat, 0x360000,0x4000, zb_fct, data, fat, 0x364000,0x1000, zb_nvram, data, fat, 0x365000,0x4000, spiffs, data, spiffs, 0x369000,0x97000, ``` Has anyone crafted a working custom partition scheme that provides more program space while staying within 4MB and enabling both OTA and Zigbee? ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [November 2, 2025, 2:49am UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249/2 "2025-11-02T02:49:05Z")
I find claude.ai to be generally _pretty_ good at these kinds of things, [it had a few seemingly helpful suggestions over here](https://claude.ai/share/d5c8bbcd-eb8e-42f6-8643-d076be24e9ae) that might help get it goin’ (the first 2 sound very viable to me!) ---
**Author:** ![JohnLand](https://avatars.discourse-cdn.com/v4/letter/j/d2c977/32.png) [@JohnLand](https://community.sparkfun.com/u/JohnLand)\ **Post date:** [November 2, 2025, 5:55am UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249/3 "2025-11-02T05:55:29Z")
LOL! That was ME, querying Claude to solve this problem. None of that worked (and Claude and I went back and forth for a couple of hours to trying different things). So that’s why I posted my query here, in case someone had more experience (and good luck!) than Claude. ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [November 2, 2025, 11:25pm UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249/4 "2025-11-02T23:25:10Z")
It might help to post in the espressif forum for the C6 or maybe also on stackoverflow…but hopefully someone here has some experience and can show us the light ---
**Author:** ![JohnLand](https://avatars.discourse-cdn.com/v4/letter/j/d2c977/32.png) [@JohnLand](https://community.sparkfun.com/u/JohnLand)\ **Post date:** [April 19, 2026, 11:01pm UTC](https://community.sparkfun.com/t/help-needed-for-zigbee-custom-partition-scheme-for-esp32-c6-qwiic-pocket/67249/5 "2026-04-19T23:01:40Z")
I realized I never updated my question with the answer. Note also: 1. **For the Arduino IDE 3.3.x, put your custom CSV file in the same directory as your sketch.** 2. **The file must be named exactly: partitions.csv** 3. **In Arduino IDE: Go to Tools → Partition Scheme and select “Custom”** 4. **Build and upload. The IDE will automatically detect and use the partitions.csv in your sketch’s folder instead of the default one from the ESP32 package.** ```auto # ============================================================================= # partitions.csv — ESP32-C6 Custom Partition Table # ============================================================================= # # Target hardware : Arduino Nesso N1 (ESP32-C6, 16 MB flash) # SparkFun ESP32-C6 Qwiic Pocket (4 MB flash) # Flash mapped : First 4 MB (0x000000 – 0x3FFFFF) # On the 16 MB Nesso N1 the remaining 12 MB is unused by # this table — no partitions are defined beyond 0x3FFFFF. # OTA capable : Yes — two equal-sized app slots (app0 / app1) # Zigbee capable : Yes — three dedicated Zigbee stack partitions # # ----------------------------------------------------------------------------- # FULL FLASH MAP (including regions not defined in this table) # ----------------------------------------------------------------------------- # # Address range Size Name / role # ───────────────────────────────────────────────────────────────────────── # 0x000000 – 0x007FFF 32 KB Bootloader [NOT in table — hardcoded by IDF] # 0x008000 – 0x008FFF 4 KB Partition table itself [NOT in table] # ───────────────────────────────────────────────────────────────────────── # 0x009000 – 0x00DFFF 20 KB nvs (NVS / Preferences) # 0x00E000 – 0x00FFFF 8 KB otadata (active OTA slot selector) # 0x010000 – 0x1BFFFF 1728 KB app0 (OTA slot 0 — factory / primary) # 0x1C0000 – 0x36FFFF 1728 KB app1 (OTA slot 1 — OTA target) # 0x370000 – 0x373FFF 16 KB zb_storage (Zigbee network data) # 0x374000 – 0x374FFF 4 KB zb_fct (Zigbee factory config) # 0x375000 – 0x378FFF 16 KB zb_nvram (Zigbee NVRAM / binding tables) # 0x379000 – 0x3F4FFF 496 KB spiffs (SPIFFS filesystem) # 0x3F5000 – 0x3FEFFF 40 KB coredump (crash dump storage) # 0x3FF000 – 0x3FFFFF 4 KB phy_init (RF / PHY calibration data) # ───────────────────────────────────────────────────────────────────────── # TOTAL (partitions only) 4060 KB ← + 36 KB bootloader/table = 4096 KB # = 4 MB (entire first bank) # # ----------------------------------------------------------------------------- # OTA SLOT SIZING NOTE # ----------------------------------------------------------------------------- # Both app slots must be identical in size. 1728 KB (0x1B0000) was chosen to # leave room for the Zigbee, SPIFFS, coredump, and phy_init partitions while # keeping everything within the first 4 MB. The compiled sketch must be # smaller than 1728 KB for OTA updates to succeed; Arduino IDE shows binary # size after compile — check it against this limit. # # After a successful OTA upload, "otadata" is updated to point to the new # slot. On the next boot the IDF bootloader reads "otadata", validates the # new image, and launches it. If validation fails, it rolls back to the # previous slot automatically. # # ----------------------------------------------------------------------------- # ZIGBEE PARTITION NOTE # ----------------------------------------------------------------------------- # The ESP32-C6 Zigbee stack (esp-zigbee-sdk) requires exactly three # FAT-typed partitions with these exact names. Renaming or removing any of # them breaks Zigbee initialisation at runtime: # # zb_storage — Primary Zigbee NVS: network key, PAN ID, channel, device # address table, neighbour table, and other stack state that # must survive reboots. Zigbee.factoryReset() wipes this. # zb_fct — Factory configuration written once at first join and used # as the baseline for factory-reset restoration. # zb_nvram — Secondary Zigbee NVRAM: binding table, group table, and # additional stack state. Also wiped by Zigbee.factoryReset(). # # All three use SubType "fat" so the Zigbee stack can use the FAT layer # directly without going through the main NVS key-value store. # # ============================================================================= # Column reference # Name — Partition label (max 16 chars); used by esp_partition_find() # Type — "app" (executable) or "data" (everything else) # SubType — Qualifies Type; see esp-idf docs for full list # Offset — Byte address in flash; must be 4 KB-aligned (0x1000) # App partitions must additionally be 64 KB-aligned (0x10000) # Size — Partition size in bytes; must be a multiple of 4 KB (0x1000) # Flags — Optional; "encrypted" to enable flash encryption for this slot # ============================================================================= # Name, Type, SubType, Offset, Size, Flags # ── System / NVS ───────────────────────────────────────────────────────────── # Standard ESP-IDF NVS (Non-Volatile Storage) partition. # Used by the Arduino Preferences library to persist settings across reboots: # OTA mode flag, WiFi-mode flag, and the rapid-reboot OTA timestamp. # 20 KB is the IDF-recommended minimum; larger is needed only if many # Preferences namespaces are in use simultaneously. nvs, data, nvs, 0x9000, 0x5000, # ── OTA Bookkeeping ────────────────────────────────────────────────────────── # OTA data partition — mandatory when using two OTA app slots. # The IDF bootloader reads this 8 KB region to decide which app slot # (app0 or app1) contains the currently valid firmware image. On a clean # flash it is blank and the bootloader defaults to app0. After a successful # OTA upload the Zigbee-side "zigbee-mode" reboot or ElegantOTA library # updates this partition to point to the newly written slot. # Must be exactly 8 KB (0x2000) and must sit at 0xE000 — both are IDF # requirements. otadata, data, ota, 0xE000, 0x2000, # ── Application Slots (OTA) ────────────────────────────────────────────────── # Two equal-sized OTA application slots — both must be the same size. # The bootloader selects the active slot based on "otadata" above. # # app0 (OTA slot 0) — 1728 KB (0x1B0000) # Factory / primary slot. This is where the sketch is written on first # flash via USB. Must start at a 64 KB boundary (0x10000 is standard). app0, app, ota_0, 0x10000, 0x1B0000, # app1 (OTA slot 1) — 1728 KB (0x1B0000) # OTA target slot. ElegantOTA writes the incoming firmware here while # app0 continues running. Identical size to app0 is required; the IDF # will reject an OTA image that is larger than the target slot. app1, app, ota_1, 0x1C0000, 0x1B0000, # ── Zigbee Stack Partitions ─────────────────────────────────────────────────── # Three FAT partitions required by the ESP32-C6 Zigbee stack. # Names, types, and subtypes are fixed — the stack locates them by name. # See ZIGBEE PARTITION NOTE in the header above for full details. # zb_storage — 16 KB: primary Zigbee network state (NWK key, PAN, channel…) # Wiped by Zigbee.factoryReset() to force a clean re-pair with the hub. zb_storage, data, fat, 0x370000, 0x4000, # zb_fct — 4 KB: Zigbee factory / calibration configuration (written once). zb_fct, data, fat, 0x374000, 0x1000, # zb_nvram — 16 KB: Zigbee binding table, group table, and additional NVRAM. # Also wiped by Zigbee.factoryReset(). zb_nvram, data, fat, 0x375000, 0x4000, # ── General-Purpose Filesystem ──────────────────────────────────────────────── # SPIFFS (SPI Flash File System) — 496 KB (0x7C000). # Used by ElegantOTA and the web control panel (WiFi-only / OTA modes) to # serve static assets. Also available for user configuration files or logs. # SPIFFS has no subdirectory support; filenames are flat paths up to 32 chars. # Alternative: replace with "LittleFS" (same SubType spelling in IDF >= 5.x). spiffs, data, spiffs, 0x379000, 0x7C000, # ── Crash Diagnostics ───────────────────────────────────────────────────────── # Core dump partition — 40 KB (0xA000). # When a crash occurs and core dump to flash is enabled in sdkconfig, the IDF # exception handler serialises CPU registers, stack frames, and heap state # here. Retrieve and decode post-mortem with: # idf.py coredump-info (requires ELF with debug symbols) # 40 KB is sufficient for single-core ESP32-C6 with a modest stack depth. # This partition is never written during normal operation. coredump, data, coredump,0x3F5000, 0xA000, # ── RF Calibration Data ─────────────────────────────────────────────────────── # PHY init data — 4 KB (0x1000) at the very top of the 4 MB region. # Contains RF calibration tables and PHY configuration used by the # radio subsystem at boot. Written by the factory test process; the IDF # reads it before initialising WiFi or the 802.15.4 (Zigbee) radio. # 0x3FF000 is the standard IDF location — do not move this partition. phy_init, data, phy, 0x3FF000, 0x1000, ```