I’m trying to get a 5G connection up and running with Quectel RG255C-GL-AB but am failing to open any control-channel session.
In MBIM mode: The module returns MBIM_OPEN_DONE with status MBIM_STATUS_FAILURE (0x00000002) and with a mismatched transaction ID. This ultimately results in failure (ModemManager) or a timeout after repeated retries (libmbim / mbimcli).
Every attempt to open the MBIM control channel fails; mbimcli captured the following exchange:
sent: 01:00:00:00:10:00:00:00:06:00:00:… (MBIM_OPEN, transaction=6)
received: 01:00:00:80:10:00:00:00:00:00:00:… (MBIM_OPEN_DONE, transaction=0, status=FAILURE)
I’ve tried firmware versions RG255CGLABR01A04M4G and RG255CGLABR01A05M4G_A0.300.A0.300, and two different hosts [Debian gateway, kernel 6.12.86+deb13-amd64, ModemManager 1.24.0; and Debian 13 VM (UTM on Apple host), libmbim-utils / mbimcli only, no ModemManager]
In QMI mode: After manually binding 2c7c 0316 to qmi_wwan, all qmicli transactions are also timing out with the message
error: couldn’t open the MbimDevice: Operation timed out: device is closed.
I believe this is an control-channel specific issue as:
- LTE registration, SIM access and bearer activation via plain AT commands works
- a PPP data session was also tested on the gateway. Authentication completes successfully, but the session is silently dropped during IPCP negotiation with no further diagnostic detail returned by the modem.
What can I try to resolve this?