Trouble updating custom weather station firmware

I have tried to build a custom Weather Station firmware according to the guide in

I Modified only the BLE_TX_POWER to 10 and APP_CFG_NON_CONN_ADV_INTERVAL_MS to MSEC_TO_UNITS(5000, UNIT_0_625_MS). The firmware built without errors and made the DFU package with the --debug-mode -flag as described in the guide. After that, I successfully uploaded the firmware to the tag with iOS nRF Toolbox.

After the upload, the red LED on the tag is constantly on as if the tag doesn’t get past the bootloader or something?

Any idea what went wrong? All the help is much appreciated.


Maximum transmission power is +4dBm, the power is set in discrete steps. For more details please refer to the Nordic documentation.

Since the 10 dBm is invalid value, the boot-up sequence will return error code. Ruuvi Firmware will leave RED led on if there is error during boot. To fix the problem you can use +4dBm.

That did the trick, thanks for the help!

The transmission power was at 4 in the git. Does that mean that the transmission power is already at maximum in the official weather station firmware (dated 20170418) also?

The latest official firmware has full power.
Kickstarter devices shipped with +0dBm.

Thanks for the info!