An example would make easier to understand what the problem is.
The following is just an example.
When passing this as $options:
$options = array();
$options["1"] = array("value" => "1", "text" => JText::_("ENUM_DAY_MONDAY"));
$options["2"] = array("value" => "2", "text" => JText::_("ENUM_DAY_TUESDAY"));
$options["3"] = array("value" => "3", "text" => JText::_("ENUM_DAY_WEDNESDAY"));
$options["4"] = array("value" => "4", "text" => JText::_("ENUM_DAY_THURSDAY"));
$options["5"] = array("value" => "5", "text" => JText::_("ENUM_DAY_FRIDAY"));
$options["6"] = array("value" => "6", "text" => JText::_("ENUM_DAY_SATURDAY"));
$options["7"] = array("value" => "7", "text" => JText::_("ENUM_DAY_SUNDAY"));
to this:
$jdomOptions = array_merge(array(
'dataKey' => $this->getOption('name'),
'domClass' => $this->getOption('class'),
'domId' => $this->id,
'domName' => $this->name,
'dataValue' => (string)$this->value,
'labelKey' => $this->getOption('labelKey'),
'list' => $options,
'listKey' => $this->getOption('listKey'),
'nullLabel' => $this->getOption('nullLabel'),
'responsive' => $this->getOption('responsive'),
'submitEventName' => ($this->getOption('submit') == 'true'?'onclick':null),
'viewType' => $this->getOption('viewType')
), $this->jdomOptions);
$this->input = JDom::_('html.form.input.radio', $jdomOptions);
the JDOM doesn't read the list, and the render has options with no attributes, because it's expecting an OBJECT and we are passing an ARRAY.
FIX
add the following code to the line 78 of the file dom\html\form\input\select\radio.php
