--- title: "nRF5 to nRF Connect SDK migration via DFU over BLE" url: https://daily.dev/posts/nrf5-to-nrf-connect-sdk-migration-via-dfu-over-ble-emmwx1hik source_url: https://www.embeddedrelated.com/showarticle/1573.php type: article source: "EmbeddedRelated" published: 2026-05-31T07:48:02.175Z updated: 2026-05-31T09:11:35.899Z tags: ["embedded", "bluetooth"] reading_time: 8 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # nRF5 to nRF Connect SDK migration via DFU over BLE **[EmbeddedRelated](https://daily.dev/sources/embeddedrelated)** · 8 min read · 0 upvotes · 0 comments ## Summary Nordic Semiconductor deprecated the nRF5 SDK in favor of the nRF Connect SDK (NCS), but provides no official DFU path to migrate already-shipped devices over BLE. This post details a practical workaround for the nRF52840 using external SPI flash. The approach involves: DFU-ing a modified nRF5 bootloader that disables ACL flash protection, creating a custom BLE service to stream a merged NCS binary (MCUBoot + application) into external SPI flash, then executing RAM-resident code with interrupts disabled to erase internal flash and copy the new image starting at address 0. Key implementation details include using GCC's section attribute to relocate code to RAM, polling-based NVMC writes, XIP memory-mapped access to QSPI flash, and disabling IRQs before erasing interrupt vectors. The method has been confirmed working on both nRF52840 and nRF52833. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [KAGA FEI ES4L15MA1 is a ridiculously small, ready-to-use BLE 6.0 module based on Nordic nRF54L15 SoC](https://daily.dev/posts/kaga-fei-es4l15ma1-is-a-ridiculously-small-ready-to-use-ble-6-0-module-based-on-nordic-nrf54l15-soc-iqcwwmjyh) · CNX Software · 1 upvotes · 0 comments - [Icy Electronics nRF54L15 Discovery devboard integrates a snappable nRF52820 CMSIS-DAP debugger](https://daily.dev/posts/icy-electronics-nrf54l15-discovery-devboard-integrates-a-snappable-nrf52820-cmsis-dap-debugger-9xqyboo52) · CNX Software · 0 upvotes · 0 comments - [nRF54L Arduino Core project brings Arduino support to Nordic Semi nRF54L wireless SoCs](https://daily.dev/posts/nrf54l-arduino-core-project-brings-arduino-support-to-nordic-semi-nrf54l-wireless-socs-gxiujnqgp) · CNX Software · 0 upvotes · 0 comments --- Tags: [#embedded](https://daily.dev/tags/embedded), [#bluetooth](https://daily.dev/tags/bluetooth) [View this post on daily.dev](https://daily.dev/posts/nrf5-to-nrf-connect-sdk-migration-via-dfu-over-ble-emmwx1hik)