index.js line 74 - /info/getLocations checks for definition of type parameter, which breaks older STB compatibility. Comments note that this may be erroneous.

[Numbski]

For the sake of not repeating a whole lot of typing, I'm going to link a downstream project issue that I opened for this before I understood that the problem was actually upstream:

ToddGreenfield/homebridge-directv#17

In very, very brief terms - older set top boxes are compatible (mostly), but they do not support the type argument to /info/getLocations, and depending on how pervasive this is in the code, it could come up elsewhere. Using one of my own STBs as an example:

pi@homebridge:~/scripts/directv$ curl http://172.16.30.79:8080/info/getLocations | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   195  100   195    0     0   1772      0 --:--:-- --:--:-- --:--:--  1772
{
  "locations": [
    {
      "clientAddr": "0",
      "locationName": "LIVING ROOM"
    }
  ],
  "status": {
    "code": 200,
    "commandResult": 0,
    "msg": "OK.",
    "query": "/info/getLocations"
  }
}

Note that "type" isn't being sent. Now let's look at what directv-remote attempts to send to that receiver:

172.16.30.28.54386 > 172.16.30.76.http-alt: Flags [P.], cksum 0x9505 (incorrect -> 0x27e4), seq 1:87, ack 1, win 502, options [nop,nop,TS val 1843789388 ecr 516813839], length 86: HTTP, length: 86
	GET /info/getLocations?type=1 HTTP/1.1
	Host: 172.16.30.76:8080
	Connection: close

/info/getLocations?type=1

If I attempt to do that, here's what happens:

pi@homebridge:~/scripts/directv$ curl http://172.16.30.79:8080/info/getLocations?type=1
{"status": {
  "code": 403,
  "commandResult": 1,
  "msg": "Forbidden.Invalid URL parameter(s) found.",
  "query": "/info/getLocations?type=1"

Which makes sense, because if you poll /info/getOptions, you get this back:

pi@homebridge:~/scripts/directv$ curl http://172.16.30.79:8080/info/getOptions | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  5873  100  5873    0     0  20607      0 --:--:-- --:--:-- --:--:-- 20679
{
  "options": [
    {
      "command": "/info/getLocations",
      "description": "List of available client locations. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        }
      ]
    },
*snip*

It only supports wrapper and callback. Neither is required. So if we bounce back over to your code, we have this block:

    // "List of available client locations."
    // Returns an array of the networked set top boxes
    // type is an optional parameter
    //  the docs label it as 'int'
    //  only 0 and 1 aren't *Forbidden*
    //  i'm not sure what the difference is yet,
    //  but 1 shows more of my wireless Genie STBs
this.getLocations = function(type, callback){
        var path = '/info/getLocations';

        var options = {
            hostname: this.IP_ADDRESS,
            port: 8080,
            path: path
        };

        if (typeof type !== 'undefined') {
            options.path = buildQueryString(options.path, { type: type });
        }

        makeRequest(options, callbackHandler(callback));
    };

So type is "optional", but then a bit further down we check to make sure type isn't undefined. If it is, we don't do anything. If it isn't, we makeRequest(). Best I can tell, there's a line missing to call buildQueryString without the type parameter, probably inside of an else something like this (not a nodeJS dev, please correct if I have syntactical mistakes!):

        if (typeof type !== 'undefined') {
            options.path = buildQueryString(options.path, { type: type });
        }
       else {
              options.path = buildQueryString(options.path);
       }

That way we build the query string no matter what, and then makeRequest should handle the rest from there.

For the sake of completeness, here is the full output of /info/getOptions. I can make a cursory scan to see if this "type" business is present anywhere else, but it is a comparison that will be challenging without output of a more modern set of hardware. My suspicion is that on older hardware, type wasn't defined. On newer genie-era hardware type 0 is likely a standalone STB, and type 1 is a genie with child units. Either way, I think my solution solves for that. Again, not a nodeJS dev - need to go spelunking on my filesystem and see if I can apply this fix and see it work.

{
  "options": [
    {
      "command": "/info/getLocations",
      "description": "List of available client locations. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        }
      ]
    },
    {
      "command": "/info/getSerialNum",
      "description": "STB serial number. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        }
      ]
    },
    {
      "command": "/info/getVersion",
      "description": "Set-top-box and SHEF information. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        }
      ]
    },
    {
      "command": "/info/mode",
      "description": "Set-top-box mode. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        }
      ]
    },
    {
      "command": "/remote/processKey",
      "description": "Process a key request from the remote control. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "hold",
          "type": "string"
        },
        {
          "isRequired": true,
          "name": "key",
          "type": "string"
        }
      ]
    },
    {
      "command": "/serial/processCommand",
      "description": "Process a command request from remote control. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": true,
          "name": "cmd",
          "type": "hex"
        }
      ]
    },
    {
      "command": "/tv/getProgInfo",
      "description": "Program information of specified channel at current or specific time. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "minor",
          "type": "int"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": true,
          "name": "major",
          "type": "int"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "time",
          "type": "long"
        }
      ]
    },
    {
      "command": "/tv/getTuned",
      "description": "Information about the currently viewed program. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "videoWindow",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        }
      ]
    },
    {
      "command": "/tv/tune",
      "description": "Tune to a channel. Warning: This command may change or be disabled in the future.",
      "formControls": [],
      "urlParameters": [
        {
          "isRequired": false,
          "name": "wrapper",
          "type": "string"
        },
        {
          "isRequired": false,
          "name": "minor",
          "type": "int"
        },
        {
          "isRequired": false,
          "name": "callback",
          "type": "string"
        },
        {
          "isRequired": true,
          "name": "major",
          "type": "int"
        },
        {
          "isRequired": false,
          "name": "source",
          "type": "int"
        },
        {
          "isRequired": false,
          "name": "clientAddr",
          "type": "string"
        }
      ]
    }
  ],
  "status": {
    "code": 200,
    "commandResult": 0,
    "msg": "OK.",
    "query": "/info/getOptions"
  }
}