FIRMWARE OVER THE AIR

[Rachita Reddy]

Here is a professional and technically detailed ticket template you can use to submit to Nordic Semiconductor (DevZone), Quectel Support, or your internal System Architect/Lead.

I have structured this to clearly highlight the hardware setup, the software stack, and the specific memory constraint issue.

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Ticket Subject:

Urgent: Firmware Binary Size (598KB) Exceeds FOTA Partition Limit (150KB) on nRF5340 + Quectel EC200 Gateway

Ticket Description:

Device Overview:

• Device Type: IoT Gateway

• MCU: Nordic nRF5340 (Application Core)

• Connectivity Module: Quectel EC200 (connected via UART/USB)

• RTOS: Zephyr RTOS (nRF Connect SDK v2.x.x) [Insert your specific SDK version here]

• Cloud Provider: AWS IoT Core

Functional Summary:

The gateway acts as a central hub. It scans for BLE Nodes using Extended Advertising packets, processes the data, and pushes it to the cloud via the Quectel EC200 modem using the AWS IoT library over HTTPS/MQTT.

The Problem:

We are implementing FOTA (Firmware Over-The-Air) updates. The current compiled application binary (app_update.bin / zephyr.signed.bin) is approximately 598 KB.

However, our current flash memory partitioning / download slot allocation appears to be restricted to 150 KB. We are unable to perform the FOTA update because the new image does not fit into the secondary slot.

Technical Constraints & Configuration:

1. Current Build Size: ~600KB (Includes Zephyr Kernel, MCUboot, BLE Host, Extended Adv support, AWS IoT Stack, Modem Drivers).

2. Target Size Limit: ~150KB (This seems unusually low for the nRF5340 App Core which has 1MB Flash).

3. Bootloader: MCUboot enabled (CONFIG_BOOTLOADER_MCUBOOT=y).

Steps Taken So Far:

1. Enabled standard FOTA configurations (CONFIG_AWS_FOTA, CONFIG_FOTA_DOWNLOAD).

2. Attempted to optimize logging, but the size reduction is insufficient.

Requests for Support:

1. Partition Manager: Is the 150KB limit a hard constraint of the default partition manager configuration? How can we adjust pm_static.yml to increase the secondary slot size on the nRF5340?

2. Optimization: Given that we require the AWS Stack (which relies on mbedTLS) and BLE Extended Advertising, what are the recommended Kconfig options to aggressively strip unused drivers and symbols to reduce the binary size?

3. Modem Offloading: Is it possible to offload the AWS TLS/SSL stack to the Quectel EC200 modem (using modem-internal TCP/IP stack) to remove the heavy mbedTLS library from the nRF5340 application code?

 

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[Vidar Berg]

Hello,

Please post your current pm_static.yml file so I can see how you have partitioned your memory.

Best regards,

Vidar

[Rachita Reddy]

EMPTY_0:

  address: 0xfd000

  end_address: 0x100000

  placement:

    after:

    - settings_storage

  region: flash_primary

  size: 0x3000

app:

  address: 0x15200

  end_address: 0xfc000

  region: flash_primary

  size: 0xe6e00

external_flash:

  address: 0xe7000

  end_address: 0x800000

  region: external_flash

  size: 0x719000

mcuboot:

  address: 0x0

  end_address: 0x15000

  placement:

    before:

    - mcuboot_primary

  region: flash_primary

  size: 0x15000

mcuboot_pad:

  address: 0x15000

  end_address: 0x15200

  placement:

    before:

    - mcuboot_primary_app

  region: flash_primary

  size: 0x200

mcuboot_primary:

  address: 0x15000

  end_address: 0xfc000

  orig_span: &id001

  - app

  - mcuboot_pad

  region: flash_primary

  size: 0xe7000

  span: *id001

mcuboot_primary_app:

  address: 0x15200

  end_address: 0xfc000

  orig_span: &id002

  - app

  region: flash_primary

  size: 0xe6e00

  span: *id002

mcuboot_secondary:

  address: 0x0

  device: DT_CHOSEN(nordic_pm_ext_flash)

  end_address: 0xe7000

  placement:

    align:

      start: 0x4

  region: external_flash

  share_size:

  - mcuboot_primary

  size: 0xe7000

otp:

  address: 0xff8100

  end_address: 0xff83fc

  region: otp

  size: 0x2fc

pcd_sram:

  address: 0x20000000

  end_address: 0x20002000

  placement:

    after:

    - start

  region: sram_primary

  size: 0x2000

rpmsg_nrf53_sram:

  address: 0x20070000

  end_address: 0x20080000

  placement:

    before:

    - end

  region: sram_primary

  size: 0x10000

settings_storage:

  address: 0xfc000

  end_address: 0xfd000

  placement:

    align:

      start: 0x4000

    before:

    - end

  region: flash_primary

  size: 0x1000

sram_primary:

  address: 0x20002000

  end_address: 0x20070000

  region: sram_primary

  size: 0x6e000

[Vidar Berg]

Where are you seeing that the slots are 150 kB? You partition file show that they are 0xe7000 bytes. 

[Rachita Reddy]

 iam getting the error log as 150kb max we have our own dash board