Failed to write factory almanac (65536)

[nrao32]

I'm trying out the GNSS sample for the nRF9161 DK. I am trying to enable minimal assistance, but I get an error message with error code 65536:

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using Zephyr OS v3.6.99-100befc70c74 ***
[00:00:09.889,648] <err> projectnamehere: Failed to write factory almanac

The error in question occurs here:
https://github.com/nrfconnect/sdk-nrf/blob/54f8a63b22d4b94398774334aa85ace6a5e20459/samples/cellular/gnss/src/assistance_minimal.c#L115

Any ideas what might be going on here? GNSS still works afterwards and TTFF is about a minute.

BTW, the modem firmware is latest (mfw_nrf91x1_2.0.1).

[Hakon]

Modem team;

Based on the application output, my guess is that they are not running an unmodified GNSS sample. I tried the GNSS sample from SDK v2.7.0 with nRF9151 and MFW v2.0.1, and it works fine.

If the almanac data and checksum are correct, there are only two reasons why the writing should fail. One is that the modem is in active state and second that power off warning (configured with %XPOFWARN) is currently active. The second one is unlikely the reason here, if they are using a DK and the nRF9161 is powered from the USB. They should check if the application sets the modem to active state before the factory almanac is written. If that’s the case, they need to change their implementation. %XFILEWRITE can only be done in +CFUN modes 0 and 4.

[nrao32]

I tried to move that code to the very beginning of the application, but now I get error code -1 (instead of 65536). I tried to update the mode like so at the beginning prior to any other func calls:

err = nrf_modem_at_printf("AT+CFUN=0");
if (err != 0) {
    LOG_ERR("Failed to set mode, error: %d", err);
    return;
}

This did not work, and resulted in the message: "Failed to set mode, error: -1"

If I move that code which calls the almanac function to where it is in the sample, I get the original 65536 error code:

https://github.com/nrfconnect/sdk-nrf/blob/c94e86f50a38e200e449bdf2a3f0008037ca4933/samples/cellular/gnss/src/main.c#L723

[nrao32]

I was just able to get the sample to work as well -- there must be something wrong with my code. I'll keep digging in. Thank you for the pointers.

EDIT: confirmed, it was a bug in my code, and I originally got confused because I messed up the prj.conf on the sample while learning/digging my way around.