RG255C-GL (RedCap) module not connecting to 5G SA

Technical Subjects Upgrade/Debug
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1

Hello,

I have an RG255C-GL (RedCap) module inside a Teltonika RUT271 router, firmware RG255CGLABR01A04M4G_A0.004.A0.004.

It cannot attach to our private 5G SA network (Open5GS core, PLMN 999-12/001-01, Askey small cell, band n48/n78, 20 MHz, SA only):

  • AT+QSCAN=3,1 detects the cell strongly (RSRP −52 to −77 dBm), correct PLMN/band/bandwidth

  • AT+QENG="servingcell" stays “SEARCH” forever; +C5GREG: 2,0

  • Manual selection AT+COPS=1,2,"<plmn>",11 fails

  • AT+QNWPREFCFG="mode_pref",NR5G + "nr5g_band" lock to the correct band — no change

  • SIM is provisioned and valid (verified: full-capability modules RM520N-GL and phones register and get PDU sessions on the same cell, same SIM profile)

  • MBN is default ROW_Commercial, AutoSel=1

The same cell is verified working with another RG255C-GL device running firmware RG255CGLABR01A10M4G_A0.001.A0.001 (an Askey RedCap camera attaches at 20 MHz with the same cell configuration). So this looks like a cell-selection/attach issue fixed between R01A04 and R01A10.

Could you please provide the latest RG255C-GL firmware (R01A10 or newer) and the recommended upgrade procedure for a module embedded in a Teltonika RUT271 (Linux host)? I can flash via QFirehose or the host’s modem-upgrade tooling.

Thank you!

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