Quectel RG255C-GL can´t connect to private network 5G SA

Yunus_As · October 6, 2025, 1:49pm

@silvia Hi, I have the same problem. Can you send me the related AT commands and right version?

Thank u in advance!
Yunus

silvia · October 9, 2025, 10:55am

Dear @Yunus_As
What is your problem? Can’t connect SA or others?

Yunus_As · October 9, 2025, 11:37am

Problem statement

Device/FW: Quectel RG255C-GL (5G RedCap) on Linux with qmi_wwan_q (Quectel) driver.
SIM/PLMN: 286-03 (Türk Telekom).
Status: LTE (4G) attaches and passes data. 5G cannot attach.
My Command Set:

AT+CPIN? → +CPIN: READY
AT+CFUN? → +CFUN: 1
AT+C5GREG=2 → OK (URC enabled)
AT+QNWPREFCFG=“nr5g_band” → … 1:3:7:20:28:40:41:71:77:78:79
AT+QNWPREFCFG=“mode_pref”,NR5G → OK (NR-only preference)
AT+COPS=1,2,“28603”,12 → +CME ERROR: 30
AT+C5GREG? → OK +C5GREG: 2,0

silvia · October 10, 2025, 3:43am

Dear @Yunus_As
Do you know which band of SA on your region?
n77 or others?

Please share your current firmware.

Yunus_As · October 10, 2025, 8:41am

It is n78 .

Firmware: RG255CGLABR01A04M4G

ArtV · November 18, 2025, 3:41am

Hi @silvia

I am also having issues connecting to 5G SA with Quectel RG255C-GL
Band is n78

What are the AT commands necessary?

Thanks!

silvia · November 20, 2025, 6:56am

Dear @ArtV
I have sent to you via Message, please check.

ssss · December 11, 2025, 4:05am

Good day Madam,
I am also having issues connecting to 5G SA with Quectel RG255C-GL
Band is n78

What are the AT commands necessary?

Thanks!

silvia · December 12, 2025, 5:50am

Dear @ssss
I have sent to you via Message, please check.

Vadim_Ipatov · December 30, 2025, 11:16am

Hello,
Could you please share these AT commands with me as well?
I’m having a very similar issue with the Quectel RG255C-GL.

Vadim_Ipatov · December 30, 2025, 12:29pm

AT+QGMR
RG255CGLABR01A04M4G_A0.003.A0.003
OK

AT+COPS?
+COPS: 0,0,“LMT”,7
OK

AT+QNWPREFCFG=“mode_pref”
+QNWPREFCFG: “mode_pref”,AUTO
OK

AT+QNWPREFCFG=“nr5g_band”
+QNWPREFCFG: “nr5g_band”,1:3:7:8:20:28:78
OK

AT+QENG=“servingcell”
+QENG: “servingcell”,“NOCONN”,“LTE”,“FDD”,247,01,4F4E10,180,2850,7,5,5,9CEB,-84,-10,-54,13,0,-,29
OK

AT+QNWPREFCFG=“mode_pref”,NR5G
OK

AT+QNWPREFCFG=“mode_pref”
+QNWPREFCFG: “mode_pref”,NR5G
OK

AT+COPS=?
+COPS: (1,“LV LMT”,“LMT”,“24701”,12),(1,“LV LMT”,“LMT”,“24701”,7),(3,“BITE LV”,“BITE LV”,“24705”,7),(3,“Tele2 LV”,“Tele2 LV”,“24702”,7),(1,“247 06”,“247 06”,“24706”,7),(0-4),(0-2)
OK

AT+QENG=“servingcell”
+QENG: “servingcell”,“LIMSRV”,“NR5G-SA”,“FDD”,247,01,013D39B59,213,C3FB,154570,28,1,-61,-11,6,0,66
OK

AT+COPS=1,2,“24701”,12
+CME ERROR: no network service

AT+CGDCONT?
+CGDCONT: 1,“IP”,“internet.lmt.lv”,“0.0.0.0”,0,0,0,0,“”,0
+CGDCONT: 2,“IPV4V6”,“ims”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0,“”,0
+CGDCONT: 3,“IPV4V6”,“sos”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,1,“”,0
OK

AT+QSCAN=2
+QSCAN: “NR5G”,247,01,154570,28,-62,-11,66,1
OK

silvia · January 5, 2026, 8:07am

Dear @Vadim_Ipatov
It is a different issue.
Your firmware is old, I will send newer to your email, please try again.

Alentejana · February 10, 2026, 1:34pm

Hi, I’m having similar issues as described here. Version RG255CGLABR01A04M4G_A0.300.A0.300

The cell is n40 and configured with 20MHz. There’s no issue when connecting to n28 or n1 even with the RedCap compatibility flag disabled on the gNodeB. Traces from the node show no registration attempt has been made. Could you please advise on the steps to solve the issue? Thanks.

silvia · March 3, 2026, 3:17am

Dear @Alentejana
I have sent to you via Message, please check.

Safel · March 3, 2026, 2:22pm

Hi, I have similar problem. Version RG255CGLABR01A04M4G_A0.300.A0.300

AT+C5GREG?
+C5GREG: 0,0

OK
AT+C5GREG?
+C5GREG: 0,0

OK
AT+QNWPREFCFG=“mode_pref”
+QNWPREFCFG: “mode_pref”,NR5G

OK
AT+CFUN?
+CFUN: 1

OK
AT+QENG=“servingcell”
ERROR
AT+QENG=?
+QENG: (“servingcell”,“neighbourcell”)

OK
AT+QENG=“servingcell”
+QENG: “servingcell”,“SEARCH”

OK

silvia · March 10, 2026, 8:33am

Dear @Safel
Do you also test with private network?
Please share information, band, bandwidth.

Rohit_Jagtap · March 23, 2026, 8:10pm

Hello @silvia,

I’m using the 5G REDCAP EVB - RG255C-GL, and Could you please give me the backup & restore of existing firmware from device & required documentation and tools. Is there any Linux tool available or only windows for backup and restore?

This is my device information:

AT

OK
AT+CVERSION

VERSION: RG255CGLABR01A04M4G
Jun 24 2024 15:04:10
Authors: Quectel

OK
AT+CSUB

SubEdition: V02

OK
AT+QGMR

RG255CGLABR01A04M4G_01.002.01.002

OK

Also could you please give the updated firmware for this? and how we can enable the adb & debug-logs for this? As existing firmware not shows option for this:

AT+QCFG=?

+QCFG: "rrc",(0-5)
+QCFG: "pdp/duplicatechk",(0,1)
+QCFG: "risignaltype",("respective","physical")
+QCFG: "lte/bandprior",(1-43),(1-43),(1-43)
+QCFG: "diversity/config",(0,1),(1,2),(0)
+QCFG: "div_test_mode",(0,1)
+QCFG: "usbnet",(0-3)
+QCFG: "data_interface",(0,1),(0,1)
+QCFG: "pcie/mode",(0,1)
+QCFG: "wifi/model",("fc60e","fc08e")
+QCFG: "sms_control",(0,1),(0,1)
+QCFG: "call_control",(0,1),(0,1)
+QCFG: "netmaskset",(0,1)[,<netmask>]
+QCFG: "clat",(0,1),(0,1),<prefix>,(0,32,40,48,56,64,96),<fqdn>,(0,1),(0,1,2,4,8),(0,1),(0,1),(0,1,2),(0,1,2)
+QCFG: "ntp",(1-10),(5-60)

OK

Thank You.

silvia · April 7, 2026, 2:21am

Dear @Rohit_Jagtap
I have replied in another topic, please check.