DFU Bootloader Update

RE: DFU Bootloader Update

Hieu — Fri, 09 Jan 2026 12:02:05 GMT

It's great to hear that things are working for you.

[quote user="cemile nur damnali"]As a warning, bootloader version must be bigger than the current one.[/quote]

This behavior is from the Downgrade prevention feature, controlled by NRF_DFU_APP_DOWNGRADE_PREVENTION. It is enabled by default, which I think is a good thing.

RE: DFU Bootloader Update

cemile nur damnali — Thu, 08 Jan 2026 12:40:29 GMT

Update for the situation,

I can update my bootloader with DFU. Here is the command when I creating a .zip file from .hex file of the example project,

nrfutil pkg generate --hw-version 52 --sd-req 0x0103,0x0101,0x00CB,0x00AF --bootloader-version 3 --bootloader secure_bootloader_ble_s132_pca10040.hex --key-file private.key bl_dfu_package.zip

As a warning, bootloader version must be bigger than the current one.

Also, dual-bank update is available if there is enough space for bootloader at the free space. (24kB)

RE: DFU Bootloader Update

cemile nur damnali — Thu, 08 Jan 2026 07:28:41 GMT

Hello Hieu,

Thank you for your quick answer. I forgot the tell my bootloader version as you specified. I am using pca10040_s132_ble example and I did few changes like a changing DFU advertise data etc. not more than that. Right now, my product on production stage and unfortunately, there many products on field. Actually bootloader works pretty fine too. But sometimes the customers cannot update the main application correctly from our mobile application. They forgot keep open the phone during upgrading process or their internet connection can be a total mess. In addition, my main application is larger than half of total flash. Because of that situation the product stays on the DFU stage if the upgrading process not goes right and cannot recover itself. In the current bootlader the DFU advertise data is default value "Dfutarg" but right now I have changed it to the shortening of the device name + MAC ID of the product to find the device if it is in the DFU stage or not. Thanks to this feature the customer can save their product with the new upgrade process and mobile application can confirm with the advertisement name is it true product to upgrade or not.

[quote userid="9456" url="~/f/nordic-q-a/126398/dfu-bootloader-update/558213"]Otherwise, it depends on the specifics of the bootloader you are working with.[/quote]

In short, I will try to upgrade my bootlader via the link that you send and inform you. If you have any other recommendation about the situation I will accept them gladly. Thank you for your patience.

Sincerely,

Damnali

RE: DFU Bootloader Update

Hieu — Wed, 07 Jan 2026 19:02:56 GMT

Hello Cemile,

If you have been using the same bootloader provided in the nRF5 SDK v17.1.0, with its default configurations, then it can be updated.
See: https://docs.nordicsemi.com/bundle/sdk_nrf5_v17.1.0/page/lib_bootloader_dfu_process.html#lib_bootloader_dfu_step.

Otherwise, it depends on the specifics of the bootloader you are working with.

Sincerely,

Hieu