CakePHP: Create array of checkboxes and update field based on whether it's set

I'm not sure if what I'm asking for is possible, but here's the scenario:

I have a foreach() loop that returns some values in HTML format:

<?php foreach($stuff as $s) { ?>
 <tr>
    <td><?php echo $s['Model']['data']; ?> </td>
 </tr>
<?php } ?>

What I need to do is put a checkbox next to each $s['Model']['data'], preferably with $s['Model']['data'] as the label, and be able to set a value in a table based on whether the box is checked. So, my edit.ctp would look like this:

<?php foreach($stuff as $s) { ?>
 <tr>
    <td><?php echo $this->Form->input('flag', array('type'=>'checkbox, 'default'=>'', label=>' $s['Model']['data']', 'value'=>1 )); ?> </td>
 </tr>
<?php } ?>

I have no trouble displaying the above. My problem is that I don't know how to tell my controller to update the necessary field if the labeled box is checked. Here's my first run at it:

if($this->request->save($this->request->data)) {
    foreach($stuff as $s) {
        $this->Model->id = $s['Model']['id'];
        if(isset($this->request->data['FormName']['flag'])) {
            $this->Model->set('flag', 1);
            $this->Model->save('flag', true);
        }
    }
} 

No errors at runtime, but nothing happens. The flag field in the Model I need to update remains = 0. I can debug $stuff and see data, so I know it's there. I also know that my edit function is hitting the foreach() loop. What might I be missing? Do I need to assign the checkbox a different value or check for whether it's set some other way?