hci_uart will not flash with VS Studio

RE: hci_uart will not flash with VS Studio

Simon D-M — Wed, 07 Jan 2026 12:57:53 GMT

Hi,

[quote user="Burt"]We know that it is fixed in more recent releases.[/quote]

Ok, that's what I wanted to know with my last question.

[quote user="Burt"]However, the toolchain for SDK v3.2.1 comes packaged with the broken v2.15.2. And modern nRF Connect for VS Code uses the nrfutil-device in the toolchain.[/quote]

I asked internally what is the recommended fix for this.

My guess would be to update manually the bundled nrfutil-device after install the toolchain, but I can see how it would not be scalable.

If possible, wait until I get answered before making some changes to the toolchain. I'll keep you updated on that matter as soon as I have more information !

Best regards,

Simon D-M

RE: hci_uart will not flash with VS Studio

Burt — Tue, 06 Jan 2026 13:39:04 GMT

Simon, if I may interject, on Tim's behalf: we know that the issue was non-existent in 2.15.1, as Tim showed above. The issue came about in 2.15.2 (but I believe existed in certain much older releases). We know that it is fixed in more recent releases. However, the toolchain for SDK v3.2.1 comes packaged with the broken v2.15.2. And modern nRF Connect for VS Code uses the nrfutil-device in the toolchain.

Burt

RE: hci_uart will not flash with VS Studio

Simon D-M — Tue, 06 Jan 2026 10:15:12 GMT

Hi,

[quote user="tjm1"]nrfutil-device 2.15.1 (6f9a83f 2025-10-10)[/quote]

I can see that you have the version 2.15.1 for the downloaded version. But when I download the latest version and run the same command, it tells me that I have the 2.15.6 version.

Can you please try to download the latest version (here) and retry to flash to see it the bug has been fixed in the latest version?

Best regards,

Simon D-M

RE: hci_uart will not flash with VS Studio

Timothy — Mon, 05 Jan 2026 14:55:32 GMT

Simon

my colleague Burt pointed out that I sued the "new terminal" from the terminal menu not the "open terminal". when I use the open terminal the command fails exactly as when I push the flash button. see below. nrfutil version is different in the terminal created from new terminal vs the one created in the open terminal.

Working directory: c:\Nordic4\v2.9.0
SDK: nRF Connect SDK v3.2.1
Toolchain: nRF Connect SDK Toolchain v3.2.1

PS C:\Nordic4\v2.9.0> cd ..
PS C:\Nordic4> cd .\test_n9160\central_uart_tjm\
PS C:\Nordic4\test_n9160\central_uart_tjm> nrfutil device program --serial-number 960028025 --firmware build\central_uart_tjm\zephyr\tfm_merged.hex

PS C:\Nordic4\test_n9160\central_uart_tjm> nrfutil device --version
nrfutil-device 2.15.2 (3c54c5f 2025-11-13)
commit-hash: 3c54c5feb9c6743403ce7d2026939ab443376b91
commit-date: 2025-11-13
host: x86_64-pc-windows-msvc
build-timestamp: 2025-11-13T09:29:57.574629800Z
classification: nrf-external

Detected SEGGER J-Link version: JLink_V8.76
PS C:\Nordic4\test_n9160\central_uart_tjm>

RE: hci_uart will not flash with VS Studio

Timothy — Mon, 05 Jan 2026 13:55:52 GMT

Simon

in a terminal inside VS Studio when I run the command shown below. it programs fine. see below.

PS C:\Nordic4\test_n9160\central_uart_tjm> nrfutil device program --firmware C:\Nordic4\test_n9160\central_uart_tjm\build\central_uart_tjm\zephyr\tfm_merged.hex
[00:00:02] ###### 100% [2/3 960028025] Programmed
PS C:\Nordic4\test_n9160\central_uart_tjm>

if I try to flash it in VS STudio code I still get

Executing task: nRF Connect: Flash: central_uart_tjm/central_uart_tjm (active)

Flashing central_uart_tjm to nRF9160 DK
west flash -d c:\Nordic4\test_n9160\central_uart_tjm\build --domain central_uart_tjm --dev-id 960028025

-- west flash: rebuilding
[0/5] Performing build step for 'central_uart_tjm'
[0/16] Performing build step for 'tfm'
ninja: no work to do.
[4/5] cmd.exe /C "cd /D C:\Nordic4\test_n9160\central_uart_tjm\build\_sysbuild && C:\Nordic\v1.7.0\toolchains\66cdf9b75e\opt\bin\cmake.exe -E true"
-- west flash: using runner nrfutil
-- runners.nrfutil: reset after flashing requested
-- runners.nrfutil: Flashing file: C:\Nordic4\test_n9160\central_uart_tjm\build\merged.hex

thread 'main' panicked at C:\Users\VssAdministrator\.cargo\git\checkouts\nrf-device-lib-cf1a63c495be42f5\936ac5a\serialport-lister\src\lib.rs:49:60:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Error: Subprocess C:\Nordic\v1.7.0\toolchains\66cdf9b75e\nrfutil\home\bin\nrfutil-device.exe failed with unexpected exit code Some(101)
FATAL ERROR: command exited with status 1: nrfutil --json device x-execute-batch --batch-path 'C:\Nordic4\test_n9160\central_uart_tjm\build\central_uart_tjm\zephyr\generated_nrfutil_batch.json' --seri
al-number 960028025

* The terminal process terminated with exit code: 1.
* Terminal will be reused by tasks, press any key to close it.

RE: hci_uart will not flash with VS Studio

Simon D-M — Mon, 05 Jan 2026 07:30:31 GMT

Hi,

I'm sorry for the delay. So if I understood correctly this is the output of the downloaded version. Can you please also try to run the command in the NCS bundled version so that we can compare the versions?

You can do it by opening a nRF Connect Terminal in VS Code (Go to nRF Connect extension tab and click "Open Terminal") and running the same command (nrfutil device --version) in that terminal.

Best regards,

Simon D-M

RE: hci_uart will not flash with VS Studio

Timothy — Tue, 30 Dec 2025 16:01:55 GMT

This what I see when I use the downloaded version.

if I program. this command and domwloaded version works fine.

************************************************************

C:\my_files>nrfutil device program --firmware C:\Nordic4\test_n9160\central_uart_tjm\build\central_uart_tjm\zephyr\tfm_merged.hex
[00:00:02] ###### 100% [2/3 960028025] Programmed

***************************************************************

:\my_files>nrfutil device --version
nrfutil-device 2.15.1 (6f9a83f 2025-10-10)
commit-hash: 6f9a83f9a59349b6eb90328523c41dc36b795f0a
commit-date: 2025-10-10
host: x86_64-pc-windows-msvc
build-timestamp: 2025-10-10T06:44:46.117845000Z
classification: nrf-external

Detected SEGGER J-Link version: JLink_V8.76

The device command version you are currently using was tested with a different J-Link version (JLink_V8.66) than the one you have installed (JLink_V8.76). The tested version is not required, and your J-Link version will most likely work fine. If you get issues related to J-Link with your devices, use the tested version.

RE: hci_uart will not flash with VS Studio

Timothy — Tue, 30 Dec 2025 16:01:39 GMT

This what I see when I use the downloaded version.

if I program. this command and domwloaded version works fine.

************************************************************

C:\my_files>nrfutil device program --firmware C:\Nordic4\test_n9160\central_uart_tjm\build\central_uart_tjm\zephyr\tfm_merged.hex
[00:00:02] ###### 100% [2/3 960028025] Programmed

***************************************************************

Detected SEGGER J-Link version: JLink_V8.76

RE: hci_uart will not flash with VS Studio

Simon D-M — Tue, 30 Dec 2025 13:59:51 GMT

Hi,

From what I understood from your issue, the bug is happening from the nRF Util bundled with the toolchain. I am wondering if this also happen on the "standalone" version. Can you try to download the latest version (link), and program the board with that version (nrfutil device program [OPTIONS] --firmware <PATH>)?

Can you please send me both versions' information by running this command : "nrfutil device --version" (maybe you will need to run "nrfutil.exe device --version" for the standalone version)?

From what I can see internally, it indeed should have been already patched some times ago.

If you need an alternative right now, you should be able to use nRF JProg to program the chip manually. It has been deprecated, but should still be working for older chips like the nRF9160.

Best regards,

Simon D-M

RE: hci_uart will not flash with VS Studio

Burt — Sat, 20 Dec 2025 00:35:41 GMT

Hello Simon D-M,

I work with Timothy. First, I should point out that Tim is using the 66cdf9b75e toolchain, which is 3.2.0/3.2.1 SDK. Like yourself, I was at first thrown off by the C:\Nordic\v1.7.0 prefix, but it is just an alternative to the standard C\ncs.

I managed to find this DevZone ticket nrfutil device list command fails - Nordic Q&A - Nordic DevZone - Nordic DevZone that shows that NS claimed to have fixed this issue 10 months ago. However, clearly the problem was not fixed correctly or completely (or got reverted). Can you please have the developers figure out how we could still be seeing the issue after that fix. Presumably that fix solved the issue for one individual. Is it possible that the fix was subsequently lost? This seems plausible as Tim has told me that he did not see this problem until around v3.1.0.

Thank you, Simon D-M.

Burt Silverman

RE: hci_uart will not flash with VS Studio

Simon D-M — Thu, 18 Dec 2025 12:33:34 GMT

Hi,

[quote user=""]Error: Subprocess C:\Nordic\v1.7.0\toolchains\66cdf9b75e\nrfutil\home\bin\nrfutil-device.exe failed with unexpected exit code Some(101)[/quote]

I might be wrong, but I think you are using the tool chain version 1.7.0 which is archaic... If it is the case, change to the matching toolchain version (toolchain v3.2.0) and it should work. Please keep your SDK versions and toolchain versions the same.

If it is not the case, what command / build config are you using.

I tried to build and flash this sample on my board and it worked fine. Here are the config I used :

It results in the command: west build --pristine --board nrf9160dk/nrf52840

Best regards,

Simon D-M