EM9291 on Starling 2 / VOXL 2 Only Connecting on LTE — No 5G NR Bands Detected (Firmware Issue?)

[Seungjae Baek]

Hi ModalAI team,

I’m using a Starling 2 max with the 5G modem add-on (Sierra Wireless EM9291). I’ve now fully activated a US Mobile Dark Star (AT&T) 5G plan, and the modem successfully registers on the network. However, the modem only connects over LTE and does not show any support for 5G NR bands.

Here is the current status:

1. SIM + Network Registration Working
   The SIM is active, and the module now registers correctly:

Registration state: 'registered'
CS: 'attached'
PS: 'attached'
Radio interfaces: 'lte'
PLMN: 310/410 (AT&T Dark Star)

2. No 5G NR Detection Anywhere
   All QMI queries indicate LTE-only operation:

--nas-get-serving-system → only “lte”

--nas-get-rf-band-info → EUTRAN band only

--nas-get-system-selection-preference shows:

Mode preference: cdma-1x, gsm, umts, lte, td-scdma

(There is no nr5g entry at all.)

Attempting to enable NR returns errors:

error: invalid rat mode pref value given: 'mode-preference=nr5g'

This only occurs when the modem firmware does not support NR.

3. Firmware Appears to Be LTE-Only
   Firmware reported by the module:

Modem/PRI Build ID: 02.13.08.00_GENERIC

Based on Sierra Wireless documentation, NR-capable EM9191/EM9291 firmware versions are typically in the 03.xx.xx.xx or 04.xx.xx.xx series.
The build I have (02.13.08.00_GENERIC) appears to be a pre-NR (LTE-only) firmware image.

This seems to explain:

No NR bands

No NR technology preferences

Failure to set NR mode

LTE-only operation despite 5G plan

4. Question
   Does the Starling 2 / VOXL 2 modem carrier ship with an LTE-only EM9191 firmware by default?
   If so:

Can ModalAI provide a 5G NR-capable EM9191/EM9291 firmware package (CWE/NVU)?

Or instructions for safely updating the modem firmware on VOXL 2?

My goal is to enable 5G NR (NSA/SA) operation so the drone can use the full Dark Star 5G plan.

Thanks,
Seungjae Baek

[Seungjae Baek]

@Seungjae-Baek

One more question: Should we use 5G antenna, not LTE? As I know when we buy the 5g modem the default antenna is the one with LTE.