basic - how to run first app and get printk output

RE: basic - how to run first app and get printk output

dejans — Thu, 10 Jul 2025 10:30:13 GMT

Hi,

I have tested building unmodified blinky sample in NCS v3.0.2. I can see that there is dfu_application.zip (in the build folder) which you can use to perform DFU. You can read more about dfu_application.zip in MCUBoot output build files documentation.

Best regards,
Dejan

RE: basic - how to run first app and get printk output

smmx — Wed, 09 Jul 2025 21:34:50 GMT

Hello

I followed https://www.hackster.io/Salmanfarisvp/2-makertrain-introduction-to-thingy-91x-nrf-connect-241425 - I have added

CONFIG_BOOTLOADER_MCUBOOT=y to prj.conf

I have also deleted build folder and add build config ... Then I was able to see printk that I added to code in Serial Terminal app on ttyACM0 port.

Would you maybe know what caused the problem in a first place? was CONFIG_BOOTLOADER_MCUBOOT=y the soluton?

RE: basic - how to run first app and get printk output

smmx — Wed, 09 Jul 2025 17:34:11 GMT

Hello again,

I did take a look and at https://youtu.be/S-w3-cut2E0?t=607 this timestamp, I can see commad takes app_signed.hex as firmware file. I don't see this file, below is list of all .hex files in build directory. Is any of this correct?

As first time user of this platform is really confusing for me, i'm sorry.

248 Jul 9 15:01 ./app_provision.hex

74K Jul 9 15:01 ./b0_container.hex

76K Jul 9 15:01 ./b0/zephyr/zephyr.hex

69K Jul 9 15:01 ./hello/tfm/api_ns/bin/tfm_s.hex

69K Jul 9 15:01 ./hello/tfm/bin/tfm_s.hex

210K Jul 9 15:01 ./hello/zephyr/tfm_merged.hex

146K Jul 9 15:01 ./hello/zephyr/zephyr.hex

231K Jul 9 15:01 ./hello/zephyr/zephyr.signed.hex

131K Jul 9 15:01 ./mcuboot/zephyr/zephyr.hex

560K Jul 9 15:01 ./merged.hex

128K Jul 9 15:01 ./s0.hex

128K Jul 9 15:01 ./s0_image.hex

128K Jul 9 15:01 ./s1.hex

131K Jul 9 15:01 ./s1_image/zephyr/zephyr.hex

128K Jul 9 15:01 ./signed_by_b0_mcuboot.hex

128K Jul 9 15:01 ./signed_by_b0_s1_image.hex

130K Jul 9 15:01 ./signed_by_mcuboot_and_b0_mcuboot.hex

130K Jul 9 15:01 ./signed_by_mcuboot_and_b0_s1_image.hex

RE: basic - how to run first app and get printk output

smmx — Wed, 09 Jul 2025 12:55:45 GMT

Hello Dejan,

thank you for taking time and reply.

I see there are many different firmwares that are mentioned in documentation, and this part is probably the most confusing until now 🙂

I did not enter any DFU mode. Firmware is the one that gets built by visual studio code - dfu_application.zip when i Build application. Build configuration is set for board thingy91x/nrf9151/ns.

I will take a look, I hope I gave some information to guide me where I did mistake.

I will now take a look at nrfutil guide.

Best regards
Simon

RE: basic - how to run first app and get printk output

dejans — Wed, 09 Jul 2025 12:51:37 GMT

Hi,

[quote user=""]$ nrfutil device program --firmware build/dfu_application.zip --serial-number THINGY91X_46EEE983CDD --traits mcuBoot --x-family nrf91 --core Application
[00:00:07] ###### 100% [4/4 THINGY91X_46EE...] Programmed [/quote]

Which specific firmware did you flash to your board?
Have you put your device into DFU mode before flashing? You can look at this nrfutil guide for reference.

Best regards,
Dejan