RM502Q-AE at+QNWPREFCFG="lte_band"

Thu Mar 3 17:54:19 2022 : /dev/ttyUSB2 AT+QNWPREFCFG=“lte_band”,B1:B2:B3:B4:B5:B7:B8:B12:B13:B14:B17:B18:B19:B20:B25:B26:B28:B29:B32:B66:B71
OK

Thu Mar 3 17:54:21 2022 : /dev/ttyUSB2 AT+QNWPREFCFG=“lte_band”
+QNWPREFCFG: “lte_band”,0
OK

why?

Dear Sir,
Which firmware do you test with?

Thu Mar 3 18:23:28 2022 : /dev/ttyUSB2 AT+GMR
RM502QAEAAR11A02M4G
OK

Please use the latest firmware to test, here is the at log my side.

[2022-03-04_13:18:09:639]AT+QNWPREFCFG=“lte_band”

[2022-03-04_13:18:09:639]+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

[2022-03-04_13:18:09:639]OK
[2022-03-04_13:18:12:336]ati

[2022-03-04_13:18:13:002]Quectel
[2022-03-04_13:18:13:002]RM502Q-AE
[2022-03-04_13:18:13:002]Revision: RM502QAEAAR11A04M4G

[2022-03-04_13:18:13:002]OK

That syntax is incorrect. There’s no “B”.

AT+QNWPREFCFG="lte_band",1:2:3:4:5:7:8:12:13:14:17:18:19:20:25:26:28:29:32:66:71

RM502QAEAAR11A04M4G Is there any upgrade between this firmware and my firmware?

Please see below firmware release notes.Thanks!
Quectel_RM502Q-AE-AA_Firmware_Release_Notes_V1104_01.003.01.003.pdf (946.5 KB)

So, if I am on T-Mobile, which uses B2,B4, B12, B66 and B71, and 5G bands B41 and B71. What AT commands do I need to use? Are 4G and 5G commands separate?

Yes they are separate. also, nsa and sa bands are separate. What are you trying to accomplish?
also you should issue the commands in sequence, like, you can use B20:B1
You must follow the number progression.
So, considering you want B2 B4 B12 B66 B71 as LTE bands, B41 B71 as 5G, but you are not specifying if its SA or NSA, i will give you the commands:

AT+QNWPREFCFG="lte_band",2:4:12:66:71
AT+QNWPREFCFG="nsa_nr5g_band",41:71
AT+QNWPREFCFG="nr5g_band",41:71

Also check

AT+QNWPREFCFG= "mode_pref",LTE:NR5G
AT+QNWPREFCFG="nr5g_disable_mode",0
AT+QNWPREFCFG="ue_capability_band"
AT+QNWPREFCFG="policy_band"

What is AT command for factory reset?