RM521F Fails to connect to n77/n78 on Telus Canada

ATI
Quectel
RM521F-GL
Revision: RM521FGLEAR05A02M4G
RM521FGLEAR05A02M4G_01.200.01.200

I’m having a issue where enable after enabling n77/n78 in both modes along with rest of the bands, my unit is never able to connect to it and the only way it gets any 5G NR(SA) or NSA is if I have n5 or n66 bands enabled and that too, it only connects to those two bands. If I disable those 2, it never works in any type of 5G.

On RM521F-GL All 5G (SA + NSA) and LTE bands = Enabled

For Comparison I have included my RM520N-GL results, and noticed that RM521F does not list n77/n78 in the nr5g_band in “ue_compatibility_band” and in “policy_band” results. I’ve run the commands to enable ALL bands on the RM521 but no go.

What could be the issue?, is the firmware from factory on the Quectel modem?

RM521F:
AT+QNWPREFCFG=“ue_capability_band”
+QNWPREFCFG: “gw_band”,1:2:4:5:8:19
+QNWPREFCFG: “lte_band”,1:2:3:4:5:7:8:12:13:14:18:19:20:25:26:28:29:30:32:34:38:39:40:41:42:43:46:48:66:71
+QNWPREFCFG: “nsa_nr5g_band”,1:2:3:5:7:8:12:20:25:28:38:40:41:48:66:79
+QNWPREFCFG: “nr5g_band”,1:2:3:5:7:8:12:20:25:28:38:40:41:48:66:79 [Note Missing n77/n78]

RM520N-GL
AT+QNWPREFCFG=“ue_capability_band”
+QNWPREFCFG: “gw_band”,1:2:4:5:8:19
+QNWPREFCFG: “lte_band”,1:2:3:4:5:7:8:12:13:14:17:18:19:20:25:26:28:29:30:32:34:38:39:40:41:42:43:46:48:66:71
+QNWPREFCFG: “nsa_nr5g_band”,0 (manually locked to 5G SA that is why it displays 0)
+QNWPREFCFG: “nr5g_band”,2:7:8:14:18:20:25:26:28:30:38:40:41:48:66:71:77:78:79 (I have manually selected these bands)


RM521F:
OK AT+QNWPREFCFG=“policy_band”
+QNWPREFCFG: “gw_band”,1:2:4:5:6:8:19
+QNWPREFCFG: “lte_band”,1:2:3:4:5:7:8:12:13:14:17:18:19:20:25:26:28:29:30:32:34:38:39:40:41:42:43:46:48:66:71
+QNWPREFCFG: “nsa_nr5g_band”,1:2:3:5:7:8:12:13:14:18:20:25:28:29:30:38:40:41:48:66:70:71:75:76:79
+QNWPREFCFG: **“nrdc_nr5g_band”,**1:2:3:5:7:8:12:13:14:18:20:25:28:29:30:38:40:41:48:66:70:71:75:76:79
+QNWPREFCFG: “nr5g_band”,1:2:3:5:7:8:12:13:14:18:20:25:26:28:29:30:38:40:41:48:66:70:71:75:76:79
[Note Missing n77/n78]

RM520N-GL
OK AT+QNWPREFCFG=“policy_band”
+QNWPREFCFG: “gw_band”,1:2:4:5:6:8:19
+QNWPREFCFG: “lte_band”,1:2:3:4:5:7:8:12:13:14:17:18:19:20:25:26:28:29:30:32:34:38:39:40:41:42:43:46:48:66:71
+QNWPREFCFG: “nsa_nr5g_band”,1:2:3:5:7:8:12:13:14:18:20:25:26:28:29:30:38:40:41:48:66:70:71:75:76:77:78:79
+QNWPREFCFG: “nr5g_band”,1:2:3:5:7:8:12:13:14:18:20:25:26:28:29:30:38:40:41:48:66:70:71:75:76:77:78:79

Troubleshooting, I’ve run the following commands:

  • AT+CFUN=1,1
    -AT+QNWPREFCFG=“nr5g_band”,1:2:3:5:7:8:12:13:14:18:20:25:26:28:29:30:38:40:41:48:66:70:71:75:76:77:78:79
  • AT+QNWPREFCFG=“nr5g_band” = shows n77/n78 as ON
  • AT+QNWPREFCFG= “rat_acq_order” = shows NR5G is preferred before LTE and WCDMA
  • AT+QNWCFG=“mode_pref”,NR5G
  • I have selected the ROW_Commercial MBN file and Telus_Canada MBN file, both have same result

I have also replaced the SIM card with the latest version the carrier offers, but no go. The unit refuses to connect to, while all other units work just fine such as WS1698 and GL-iNet M2 Development board both using RM520N-GL modem.

This is using the exact same sim in my RM521F and RM520N, results are that the RM521F never connects to n77/n78 no matter what I do, my RM520N can lock onto band n77/n78 no problem instantly.

Have you tried to change IM3I into that of a smartphone?

It’s not an issue of IMEI. Completely unrelated matter.

That is only applicable when you have a sim restricted to a certain IMEI or range of IMEI. Not the case with my unit.

The SIM works in any other device I pop it into with n77/n78:

  • iPhone
  • iPad
  • Nokia Fastmile Gateway
  • GL-iNet GL-X3000
  • Samsung S24

Absolutely zero changes required in any other device and it picks up the cellular bands instantly as I have strong coverage with tower nearby.

It may not be the issue in your case but don’t dismiss it entirely as I can attest from my personal experience that ISP are able to withhold certain frequency bands from certain devices with IMEI numbers of specified ranges.

It’s already been ruled out.

Anyone with a Telus connection must avoid RM521.

I’ve also tested the different MBN files, it won’t work with Telus higher bands. It’s the the modem firmware issue.