OTA over BLE Same Version Update Issue

RE: OTA over BLE Same Version Update Issue

Embel_Tech — Sun, 25 Jan 2026 07:58:46 GMT

Hello Team,

I am using an nRF52833 custom board with a no-sysbuild configuration. For OTA updates, I am creating an mcuboot.conf file.

mcuboot.conf:

CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256=y
CONFIG_BOOT_SIGNATURE_KEY_FILE="C:/Users/Embel/ibeacon_2/mcuboot_priv.pem"

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

# This file configures the MCUboot bootloader specifically
CONFIG_MCUBOOT_DOWNGRADE_PREVENTION=y
CONFIG_BOOT_UPGRADE_ONLY=y
CONFIG_BOOT_SWAP_USING_MOVE=n

# Logging
CONFIG_LOG=y
CONFIG_MCUBOOT_LOG_LEVEL_INF=y

# Serial recovery over UART
CONFIG_MCUBOOT_SERIAL=y
CONFIG_BOOT_SERIAL_UART=y
CONFIG_UART_CONSOLE=n

CONFIG_LOG_MODE_IMMEDIATE=y

CONFIG_LOG_BACKEND_UART=y
CONFIG_UART_CONSOLE=y
CONFIG_BOOT_SERIAL=y
CONFIG_BOOT_SERIAL_ENTRANCE_MODE_ALWAYS=y

prj.conf:

# Enable MCUboot bootloader
CONFIG_BOOTLOADER_MCUBOOT=y

# BLE DFU via MCUmgr (recommended helper)
CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y

# Optional: speed up DFU (automatically extends BT buffers & data length)
CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU_SPEEDUP=y

# 32 kHz RC oscillator
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME=""

# Flash support (required for MCUboot / DFU)
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y

CONFIG_MCUBOOT_IMGTOOL_SIGN_VERSION="1.1.6+0"

RE: OTA over BLE Same Version Update Issue

Rohit15 — Sat, 24 Jan 2026 18:34:43 GMT

I am use nrf52833 custome board board no sysbuild configuration I am use in ota I am creating mcuboot.conf insidI am using an nRF52833 custom board with a no-sysbuild configuration. For OTA updates, I am creating an mcuboot.conf file.

RE: OTA over BLE Same Version Update Issue

Turbo J — Sat, 24 Jan 2026 13:22:40 GMT

On what hardware? I don't see a board specification in your post.

DK boards have UART console on by default in the sample codes.

RE: OTA over BLE Same Version Update Issue

Embel_Tech — Sat, 24 Jan 2026 12:30:47 GMT

Hello Terje,

Thank you for the clarification.

I want to see the bootloader and application logs over UART console . What configurations do I need to enable? Can you please provide the required configuration

Best regards,
Embel_Tech

RE: OTA over BLE Same Version Update Issue

tesc — Fri, 23 Jan 2026 13:58:29 GMT

Hi,

I am sorry, but there are no configurations for adding such functionality. You would have to dive into he source code and change it manually. However I highly advice against doing so, because you might just as easily inadvertently introduce new security issues.

A fundamental assumption regarding versioning and upgrades, is that you give different images different version numbers. Our current implementations seem to require that assumption to hold. Is this not a safe assumption for your project?

Regards,
Terje

RE: OTA over BLE Same Version Update Issue

Embel_Tech — Fri, 23 Jan 2026 05:41:27 GMT

"If I don’t want the same version to be accepted during OTA, what additional configuration do I need to enable or add?"

i don't want same version accepted CONFIG_BOOT_VERSION_CMP_USE_BUILD_NUMBER i enable this configuration

RE: OTA over BLE Same Version Update Issue

tesc — Thu, 22 Jan 2026 17:03:03 GMT

Hi,

The behavior that you observe is in line with the Downgrade protection documentation for MCUboot:

After you upload a new image and reset the development kit, MCUboot attempts to boot the secondary image. If this image has, in order of precedence, a major, minor, or revision value that is lower than the primary application image, it is considered invalid and the existing primary application boots instead.

In other words, only lower version numbers are rejected. Equal or greater version numbers will be accepted.

Please note that by default the check is on major, minor and revision (patch) numbers, not tweak. If you also want to check for the optional tweak number, you need to enable CONFIG_BOOT_VERSION_CMP_USE_BUILD_NUMBER in the MCUboot image.

As you have already found out, an upgrade to an identical image is skipped. The only way for an upgrade to the same version to happen, is therefore if you create two different images but with the same version. The protection against same-version upgrades between different images, is therefore that you never make such images with identical version in the first place. If you do make such images, then it will be possible to upgrade between them. If that is not your intended behavior, then simply do not make such images.

Regards,
Terje