# Mender MCU integration on nRF9151DK: HTTP request fails during artifact download **URL:** \ **Category:** General Discussions\ **Tags:** mender-client\ **Created:** [April 13, 2026, 3:05pm UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253 "2026-04-13T15:05:24Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Dexter9532](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/dexter9532/32/2684_2.png) [@Dexter9532](https://hub.mender.io/u/Dexter9532)\ **Post date:** [April 13, 2026, 3:05pm UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/1 "2026-04-13T15:05:24Z")
Hello Mender, I’m currently doing a full mender-mcu integration on nRF9151DK and have run into a problem during OTA artifact download. When downloading an artifact, the HTTP request fails with “Message too long”. From Nordic’s documentation, this seems related to a known nRF91 HTTPS limitation where the modem cannot handle larger TLS packets and downloads need to be split into smaller range requests: > As a temporary workaround, I patched Zephyr http.c in mender-mcu: > Right now our west manifest points to a forked mender-mcu repository where I added a patch for this: > > > These changes are needed to fix the error \`Message too long\` before downloading …artifact to nRF9151 DK. In short, the patch changes the artifact download path to use smaller HTTPS range requests on nRF91 instead of one full download response. I wanted to ask whether proper ranged artifact download support for nRF91 is something that should be handled in mender-mcu upstream. ---
**Author:** ![mirzak](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/mirzak/32/2056_2.png) [@mirzak](https://hub.mender.io/u/mirzak)\ **Post date:** [April 13, 2026, 4:21pm UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/2 "2026-04-13T16:21:03Z")
I am working with @Dexter9532 on this and just wanted to highlight this part from Nordic docs: > The nRF91 Series modem has a size limit for receiving TLS packages. The size limit depends on modem internals and is around 2 kB. See modem firmware release notes for details. The library asks the server for a content-range which must be supported by the host server when using HTTPS with the nRF91 Series devices. The workaround for the hardware limitation seems to be to use [Content-Range header - HTTP | MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Content-Range) , but it is not something Mender MCU seems to handle today. Would be interesting to hear your thoughts, and if you have already come across this problem before? I would imagine that this limitation exists on other hardware as well and content-range seems like a good idea in general? Best Regards, Mirza ---
**Author:** ![TheYoctoJester](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/theyoctojester/32/1444_2.png) [@TheYoctoJester](https://hub.mender.io/u/TheYoctoJester)\ **Post date:** [April 14, 2026, 5:12am UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/3 "2026-04-14T05:12:15Z")
hi @Dexter9532 and @mirzak, Thanks for reaching out! Looking at the linked repository, the change in question seems to be [fix: add ranged artifact download with retries for nrf91 · Dexter9532/mender-mcu@efd6c06 · GitHub](https://github.com/Dexter9532/mender-mcu/commit/efd6c065af1b7d01bfeefc424758e7b0c979a7e2), correct? At a first glance I agree with the assumption that this is probably useful for other hardware too, but it’s definitely up to @danieldrabitzius et. al. to comment. Greetz, Josef ---
**Author:** ![mirzak](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/mirzak/32/2056_2.png) [@mirzak](https://hub.mender.io/u/mirzak)\ **Post date:** [April 14, 2026, 9:06am UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/4 "2026-04-14T09:06:49Z")
> [@TheYoctoJester](#): > > Looking at the linked repository, the change in question seems to be [fix: add ranged artifact download with retries for nrf91 · Dexter9532/mender-mcu@efd6c06 · GitHub](https://github.com/Dexter9532/mender-mcu/commit/efd6c065af1b7d01bfeefc424758e7b0c979a7e2), correct? Yes, the linked patch is the workaround we are currently using. @Dexter9532 is the one who has primarily worked on the patch. ---
**Author:** ![TheYoctoJester](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/theyoctojester/32/1444_2.png) [@TheYoctoJester](https://hub.mender.io/u/TheYoctoJester)\ **Post date:** [April 14, 2026, 1:43pm UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/5 "2026-04-14T13:43:05Z")
Hi @Dexter9532, We’ve looked into the implementation and think the general concept would be a worthwhile addition to have for all platform, but the current implementation probably needs a bit of polishing. Would you be open to submit it as a PR against [GitHub - mendersoftware/mender-mcu: Mender over-the-air software updater client for microcontrollers (MCUs). · GitHub](https://github.com/mendersoftware/mender-mcu), and then we finish and upstream it there? Thanks and greets, Josef ---
**Author:** ![Dexter9532](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/dexter9532/32/2684_2.png) [@Dexter9532](https://hub.mender.io/u/Dexter9532)\ **Post date:** [April 14, 2026, 2:08pm UTC](https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-request-fails-during-artifact-download/8253/6 "2026-04-14T14:08:04Z")
Hi @TheYoctoJester, Sounds like a great idea! I have made a pull-request upstream! > > > Related to https://hub.mender.io/t/mender-mcu-integration-on-nrf9151dk-http-requ…est-fails-during-artifact-download/8253/4 Thanks 🙂 Bobo