you are correct; AT+USEROTA is not enabled in the esp-at firmware shipped with the device. I forgot that I've installed my own esp-at firmware in the past. Sorry about that.

With the esp-at firmware shipped with the device I get the same results as you:

AT+GMR
AT version:2.2.0.0(s-62ccc56 - ESP32 - Nov 12 2021 13:38:12)
SDK version:v4.2.2-76-gefa6eca8b8
compile time(fc52c33):Mar 15 2022 15:59:59
Bin version:2.2.0(WROOM-32)

AT+USEROTA=36

ERROR

Thanks
Felix

AT+USEROTA works for me

could you confirm the esp-at build your device shipped with? I'm not so much interested in getting it to work as to knowing if it works on currently shipping devices - which for me it does not.

edit: this is what i get

AT+USEROTA=104

ERROR

and the command isnt listed with AT+CMD which leads me to think its not enabled?

AT+CMD?
+CMD:0,"AT",0,0,0,1
+CMD:1,"ATE0",0,0,0,1
+CMD:2,"ATE1",0,0,0,1
+CMD:3,"AT+RST",0,0,0,1
+CMD:4,"AT+GMR",0,0,0,1
+CMD:5,"AT+CMD",0,1,0,0
+CMD:6,"AT+GSLP",0,0,1,0
+CMD:7,"AT+SYSTIMESTAMP",0,1,1,0
+CMD:8,"AT+SLEEP",0,1,1,0
+CMD:9,"AT+RESTORE",0,0,0,1
+CMD:10,"AT+SYSRAM",0,1,0,0
+CMD:11,"AT+SYSFLASH",0,1,1,0
+CMD:12,"AT+RFPOWER",0,1,1,0
+CMD:13,"AT+SYSMSG",0,1,1,0
+CMD:14,"AT+SYSROLLBACK",0,0,0,1
+CMD:15,"AT+SYSLOG",0,1,1,0
+CMD:16,"AT+SYSLSPCFG",0,0,1,0
+CMD:17,"AT+SYSLSP",0,0,0,1
+CMD:18,"AT+SYSSTORE",0,1,1,0
+CMD:19,"AT+SLEEPWKCFG",0,0,1,0
+CMD:20,"AT+SYSREG",0,0,1,0
+CMD:21,"AT+USERRAM",0,1,1,0
+CMD:22,"AT+CWMODE",0,1,1,0
+CMD:23,"AT+CWSTATE",0,1,0,0
+CMD:24,"AT+CWJAP",0,1,1,1
+CMD:25,"AT+CWRECONNCFG",0,1,1,0
+CMD:26,"AT+CWLAP",0,0,1,1
+CMD:27,"AT+CWLAPOPT",0,0,1,0
+CMD:28,"AT+CWQAP",0,0,0,1
+CMD:29,"AT+CWSAP",0,1,1,0
+CMD:30,"AT+CWLIF",0,0,0,1
+CMD:31,"AT+CWQIF",0,0,1,1
+CMD:32,"AT+CWDHCP",0,1,1,0
+CMD:33,"AT+CWDHCPS",0,1,1,0
+CMD:34,"AT+CWSTAPROTO",0,1,1,0
+CMD:35,"AT+CWAPPROTO",0,1,1,0
+CMD:36,"AT+CWAUTOCONN",0,1,1,0
+CMD:37,"AT+CWHOSTNAME",0,1,1,0
+CMD:38,"AT+CWCOUNTRY",0,1,1,0
+CMD:39,"AT+CIFSR",0,0,0,1
+CMD:40,"AT+CIPSTAMAC",0,1,1,0
+CMD:41,"AT+CIPAPMAC",0,1,1,0
+CMD:42,"AT+CIPSTA",0,1,1,0
+CMD:43,"AT+CIPAP",0,1,1,0
+CMD:44,"AT+CIPV6",0,1,1,0
+CMD:45,"AT+CIPDNS",0,1,1,0
+CMD:46,"AT+CIPDOMAIN",0,0,1,0
+CMD:47,"AT+CIPSTATUS",0,0,0,1
+CMD:48,"AT+CIPSTART",0,0,1,0
+CMD:49,"AT+CIPSTARTEX",0,0,1,0
+CMD:50,"AT+CIPTCPOPT",0,1,1,0
+CMD:51,"AT+CIPCLOSE",0,0,1,1
+CMD:52,"AT+CIPSEND",0,0,1,1
+CMD:53,"AT+CIPSENDEX",0,0,1,0
+CMD:54,"AT+CIPDINFO",0,1,1,0
+CMD:55,"AT+CIPMUX",0,1,1,0
+CMD:56,"AT+CIPRECVMODE",0,1,1,0
+CMD:57,"AT+CIPRECVDATA",0,0,1,0
+CMD:58,"AT+CIPRECVLEN",0,1,0,0
+CMD:59,"AT+CIPSERVER",0,1,1,0
+CMD:60,"AT+CIPSERVERMAXCONN",0,1,1,0
+CMD:61,"AT+CIPSSLCCONF",0,1,1,0
+CMD:62,"AT+CIPSSLCCN",0,1,1,0
+CMD:63,"AT+CIPSSLCSNI",0,1,1,0
+CMD:64,"AT+CIPSSLCALPN",0,1,1,0
+CMD:65,"AT+CIPSSLCPSK",0,1,1,0
+CMD:66,"AT+CIPMODE",0,1,1,0
+CMD:67,"AT+CIPSTO",0,1,1,0
+CMD:68,"AT+SAVETRANSLINK",0,0,1,0
+CMD:69,"AT+CIPSNTPCFG",0,1,1,0
+CMD:70,"AT+CIPSNTPTIME",0,1,0,0
+CMD:71,"AT+CIPRECONNINTV",0,1,1,0
+CMD:72,"AT+MQTTUSERCFG",0,0,1,0
+CMD:73,"AT+MQTTCLIENTID",0,0,1,0
+CMD:74,"AT+MQTTUSERNAME",0,0,1,0
+CMD:75,"AT+MQTTPASSWORD",0,0,1,0
+CMD:76,"AT+MQTTCONNCFG",0,0,1,0
+CMD:77,"AT+MQTTCONN",0,1,1,0
+CMD:78,"AT+MQTTPUB",0,0,1,0
+CMD:79,"AT+MQTTPUBRAW",0,0,1,0
+CMD:80,"AT+MQTTSUB",0,1,1,0
+CMD:81,"AT+MQTTUNSUB",0,0,1,0
+CMD:82,"AT+MQTTCLEAN",0,0,1,0
+CMD:83,"AT+HTTPCLIENT",0,0,1,0
+CMD:84,"AT+HTTPGETSIZE",0,0,1,0
+CMD:85,"AT+HTTPCPOST",0,0,1,0
+CMD:86,"AT+BLEINIT",0,1,1,0
+CMD:87,"AT+BLEADDR",0,1,1,0
+CMD:88,"AT+BLENAME",0,1,1,0
+CMD:89,"AT+BLEADVPARAM",0,1,1,0
+CMD:90,"AT+BLEADVDATA",0,1,1,0
+CMD:91,"AT+BLEADVDATAEX",0,1,1,0
+CMD:92,"AT+BLEADVSTART",0,0,0,1
+CMD:93,"AT+BLEADVSTOP",0,0,0,1
+CMD:94,"AT+BLESCANRSPDATA",0,1,1,0
+CMD:95,"AT+BLEGATTSSRVCRE",0,0,0,1
+CMD:96,"AT+BLEGATTSSRVSTART",0,0,1,1
+CMD:97,"AT+BLEGATTSSRVSTOP",0,0,1,1
+CMD:98,"AT+BLEGATTSSRV",0,1,0,0
+CMD:99,"AT+BLEGATTSCHAR",0,1,0,0
+CMD:100,"AT+BLEGATTSNTFY",0,0,1,0
+CMD:101,"AT+BLEGATTSIND",0,0,1,0
+CMD:102,"AT+BLEGATTSSETATTR",0,0,1,0
+CMD:103,"AT+BLESCANPARAM",0,1,1,0
+CMD:104,"AT+BLESCAN",0,0,1,0
+CMD:105,"AT+BLECONNPARAM",0,1,1,0
+CMD:106,"AT+BLECONN",0,1,1,0
+CMD:107,"AT+BLEDISCONN",0,0,1,1
+CMD:108,"AT+BLEDATALEN",0,0,1,0
+CMD:109,"AT+BLECFGMTU",0,1,1,0
+CMD:110,"AT+BLEGATTCPRIMSRV",0,0,1,0
+CMD:111,"AT+BLEGATTCINCLSRV",0,0,1,0
+CMD:112,"AT+BLEGATTCCHAR",0,0,1,0
+CMD:113,"AT+BLEGATTCRD",0,0,1,0
+CMD:114,"AT+BLEGATTCWR",0,0,1,0
+CMD:115,"AT+BLESPPCFG",0,1,1,0
+CMD:116,"AT+BLESPP",0,0,0,1
+CMD:117,"AT+BLESECPARAM",0,1,1,0
+CMD:118,"AT+BLEENC",0,0,1,0
+CMD:119,"AT+BLEENCRSP",0,0,1,0
+CMD:120,"AT+BLEKEYREPLY",0,0,1,0
+CMD:121,"AT+BLECONFREPLY",0,0,1,0
+CMD:122,"AT+BLESETKEY",0,1,1,0
+CMD:123,"AT+BLEENCDEV",0,1,0,0
+CMD:124,"AT+BLEENCCLEAR",0,0,1,1
+CMD:125,"AT+BLEHIDINIT",0,1,1,0
+CMD:126,"AT+BLEHIDKB",0,0,1,0
+CMD:127,"AT+BLEHIDMUS",0,0,1,0
+CMD:128,"AT+BLEHIDCONSUMER",0,0,1,0
+CMD:129,"AT+MDNS",0,0,1,0
+CMD:130,"AT+WPS",0,0,1,0
+CMD:131,"AT+CWSTARTSMART",0,0,1,1
+CMD:132,"AT+CWSTOPSMART",0,0,0,1
+CMD:133,"AT+PING",0,0,1,0
+CMD:134,"AT+CIPETHMAC",0,1,1,0
+CMD:135,"AT+CIPETH",0,1,1,0
+CMD:136,"AT+CEHOSTNAME",0,1,1,0
+CMD:137,"AT+CIUPDATE",0,1,1,1
+CMD:138,"AT+UART",0,1,1,0
+CMD:139,"AT+UART_CUR",0,1,1,0
+CMD:140,"AT+UART_DEF",0,1,1,0

ed: formatting.

I did some experiments using the Ethernet connection (not WiFi) with the following results:

• AT+USEROTA works for me (Edit: this is not enabled in the shipped firmware)
• AT+WEBSERVER works for me (after enabling it in the esp-at firmware)
• AT+CIUPDATE fails for me (by default it can only be used with Espressif supplied binaries from what I can tell)

Here are some helpful links:

• OTA upgrade overview
• which features are enabled by default on a given device
• CIUPDATE by default only usable with Espressif supplied binaries

Thanks
Felix