Can't break through ERROR 3

Brand new 5205, connected with serial and got several lines of output including an announcement of “OTAA Join Start”. All AT+ commands are rejected with ERROR 3.

Is there a way to halt what appears to be a pre-programmed Join so I can issue AT commands?

Oh, in addition, when I run the Device Firmware Upgrade Tool v1.4, it fails with “Device firmware upgrade timeout!” I’m hoping this is just another symptom of the same problem.

Hei @acb,

Error code 3 : There is an error when reading or writing the flash memory.

If am am not mistaken and the above is correct there seems to be an issue either with the firmware (unlikely) or there is an hardware issue.
The timeout issue might be unrelated.
Can you give some more information:
What happens after the join procedure retry counter expires, can you enter commands?
What happens on reboot via the button, what can you see for firmware version, etc., should be similar to the below:

How are you powering the board, are you using our Serial Port Tool?
When you look at your gateway log (if available) can you see the join request packets?


Hi Hobo,

OK, after a hardware reset the device boots up and then takes off into a Join on its own initiative:

18:30:28.499 -> RAK5205 BreakBoard software version: 1.1.16 r120
18:30:28.499 -> GPS Power on
18:30:28.566 -> LIS3DH init success
18:30:28.599 -> BME680 init success
18:30:28.875 -> T: 28.58 degC, P: 1016.17 hPa, H 30.26 %rH , G: 3459 ohms
18:30:28.908 ->
18:30:28.908 -> Selected LoraWAN 1.0.2 Region: AU915
18:30:28.908 ->
18:30:28.974 -> OTAA:
18:30:28.974 -> DevEui: 60 C5 A8 FF FE 6D 04 76
18:30:28.974 -> AppEui: 00 13 7A 10 00 00 00 00
18:30:28.974 -> AppKey: 5A 69 67 42 65 65 41 6C 6C 69 61 6E 63 65 30 39
18:30:29.012 -> OTAA Join Start…

And three minutes later…

18:33:24.665 -> OTAA Join Failed. Try again
18:33:24.665 -> OTAA:
18:33:24.665 -> DevEui: 60 C5 A8 FF FE 6D 04 76
18:33:24.665 -> AppEui: 00 13 7A 10 00 00 00 00
18:33:24.665 -> AppKey: 5A 69 67 42 65 65 41 6C 6C 69 61 6E 63 65 30 39
18:33:24.665 -> OTAA Join Start…

The region and the Euis and key were apparently preprogrammed, like some sort of a test program, maybe? Any AT command I issue gets an “ERROR 3” response… I guess that means I can’t issue commands while in Join mode. And the Device Firmware Upgrade Tool can’t connect, which I like to think has the same cause.

Is there a way can I break that until-Join loop and get control of the 5205?

I’m powering from USB and have connected with both the Serial Tool and a serial terminal on my Mac.

Thanks for your thoughts on this!


Hi @acb It seems that you are using an old firmware! Please update both the bootloader and the firmware with the latest as described here: RAK5205 Firmware update The RAK DFU Tool is only for Firmware versions higher than 3.x.x.14.

Yes, sorry… RAK tech support jumped in. Looks like a bad unit. Reflash errored out. Thanks!