I'm having the same issue after upgrading one of my Rutx09 routers to RUTX_R_00.07.04.3. Before the upgrade it was running RUTX_R_00.07.04.1 and all was fine. After the upgrade, all modem related SNMP queries started to fail. All non-modem related queries run just fine. I was and am using SNMPv3. These are the OID's that worked on version RUTX_R_00.07.04.1:
1.3.6.1.4.1.48690.2.2.1.20.1 (MRSRP)
1.3.6.1.4.1.48690.2.2.1.21.1 (MRSRQ)
1.3.6.1.4.1.48690.2.2.1.19.1 (MSINR)
1.3.6.1.4.1.48690.2.2.1.16.1 (Mobile network)
1.3.6.1.4.1.48690.2.2.1.13.1 (Mobile provider)
1.3.6.1.4.1.48690.2.2.1 (Modem status)
1.3.6.1.4.1.48690.2.2.1.17.1 (Modem temp)
When I run a walk on non-upgraded Rutx09:
19-May-23 16:49:54 (33 ms) : Walk 1.3.6.1.4.1.48690.2
19-May-23 16:49:55 (157 ms) : 1.3.6.1.4.1.48690.2.1.0 = "1" [ASN_INTEGER]
19-May-23 16:49:55 (287 ms) : 1.3.6.1.4.1.48690.2.2.1.1.1 = "1" [ASN_INTEGER]
19-May-23 16:49:55 (390 ms) : 1.3.6.1.4.1.48690.2.2.1.2.1 = "3-1" [ASN_OCTET_STR]
19-May-23 16:49:55 (517 ms) : 1.3.6.1.4.1.48690.2.2.1.3.1 = "868759038293066" [ASN_OCTET_STR]
19-May-23 16:49:55 (646 ms) : 1.3.6.1.4.1.48690.2.2.1.4.1 = "EG06-E" [ASN_OCTET_STR]
19-May-23 16:49:55 (756 ms) : 1.3.6.1.4.1.48690.2.2.1.5.1 = "Quectel" [ASN_OCTET_STR]
19-May-23 16:49:55 (870 ms) : 1.3.6.1.4.1.48690.2.2.1.6.1 = "EG06ELAR04A04M4G" [ASN_OCTET_STR]
19-May-23 16:49:55 (987 ms) : 1.3.6.1.4.1.48690.2.2.1.7.1 = "868759038293066" [ASN_OCTET_STR]
19-May-23 16:49:55 (1096 ms) : 1.3.6.1.4.1.48690.2.2.1.8.1 = "204041013112367" [ASN_OCTET_STR]
19-May-23 16:49:56 (1207 ms) : 1.3.6.1.4.1.48690.2.2.1.9.1 = "inserted" [ASN_OCTET_STR]
19-May-23 16:49:56 (1317 ms) : 1.3.6.1.4.1.48690.2.2.1.10.1 = "OK" [ASN_OCTET_STR]
19-May-23 16:49:57 (2203 ms) : 1.3.6.1.4.1.48690.2.2.1.11.1 = "Registered, home" [ASN_OCTET_STR]
19-May-23 16:49:57 (2327 ms) : 1.3.6.1.4.1.48690.2.2.1.12.1 = "-71" [ASN_INTEGER]
19-May-23 16:49:58 (3165 ms) : 1.3.6.1.4.1.48690.2.2.1.13.1 = "vodafone NL" [ASN_OCTET_STR]
19-May-23 16:49:59 (4147 ms) : 1.3.6.1.4.1.48690.2.2.1.14.1 = "20404" [ASN_OCTET_STR]
19-May-23 16:49:59 (4259 ms) : 1.3.6.1.4.1.48690.2.2.1.15.1 = "Connected" [ASN_OCTET_STR]
19-May-23 16:49:59 (4387 ms) : 1.3.6.1.4.1.48690.2.2.1.16.1 = "LTE" [ASN_OCTET_STR]
19-May-23 16:49:59 (4567 ms) : 1.3.6.1.4.1.48690.2.2.1.17.1 = "390" [ASN_INTEGER]
19-May-23 16:50:00 (5207 ms) : 1.3.6.1.4.1.48690.2.2.1.18.1 = "27715339" [ASN_OCTET_STR]
19-May-23 16:50:00 (5327 ms) : 1.3.6.1.4.1.48690.2.2.1.19.1 = "10" [ASN_INTEGER]
19-May-23 16:50:01 (6207 ms) : 1.3.6.1.4.1.48690.2.2.1.20.1 = "-98" [ASN_INTEGER]
19-May-23 16:50:01 (6327 ms) : 1.3.6.1.4.1.48690.2.2.1.21.1 = "-8" [ASN_INTEGER]
19-May-23 16:50:01 (6437 ms) : 1.3.6.1.4.1.48690.2.2.1.22.1 = "-489779017" [ASN_INTEGER]
19-May-23 16:50:01 (6547 ms) : 1.3.6.1.4.1.48690.2.2.1.23.1 = "1773386125" [ASN_INTEGER]
19-May-23 16:50:01 (6667 ms) : 1.3.6.1.4.1.48690.2.2.1.24.1 = "10.171.115.163" [ASN_OCTET_STR]
19-May-23 16:50:01 (6787 ms) : 1.3.6.1.4.1.48690.2.2.1.25.1 = "121121070" [ASN_INTEGER]
19-May-23 16:50:01 (6907 ms) : 1.3.6.1.4.1.48690.2.2.1.26.1 = "105000597" [ASN_INTEGER]
19-May-23 16:50:02 (7207 ms) : 1.3.6.1.4.1.48690.2.2.1.27.1 = "8931440301469658460F" [ASN_OCTET_STR]
When I run the same walk on the upgraded Rutx09:
19-May-23 16:51:00 (45 ms) : Walk 1.3.6.1.4.1.48690.2
19-May-23 16:51:00 (155 ms) : 1.3.6.1.4.1.48690.2.1.0 = "0" [ASN_INTEGER]