gistfile1.txt

//Use the SObject Rows resource to update records
Service.update = function(type, sfdcId, data, options) {
  var postData = {
    b: data,
    q: '/' + sfVersion + '/sobjects/' + type + '/' + sfdcId
  };

  //
  return $http.put(cmcSFProxyEndPoint, postData, {
    transformRequest: function(data, headersGetter) {
      return 'b=' + JSON.stringify(data.b) + '&q=' + data.q;
    }
  });

}

Code from the core cmc-sfdc.js file.