Bootstrap modal backdrop = 'static' not working

I had the same problem with Bootstrap 4.1.1 and it only worked when I added the data attributes to the html

<div class="modal fade show" id="myModal" tabindex="-1" role="dialog"
  style="display: block;" data-keyboard="false" data-backdrop="static">
...

Similar to Daniele Piccioni but a bit more concise:

$('#myModal').modal({backdrop: true, keyboard: false, show: true});
$('#myModal').data('bs.modal').options.backdrop = 'static';

This is for Bootstrap 3.+

See also: Change Bootstrap modal option once it already exists

I found a workaround for this issue.

Once the modal has been hidden bootstrap data still remains on it. To prevent that I had the following:

$('#myModal').modal('show'); //display something
//...

// if you don't want to lose the reference to previous backdrop
$('#myModal').modal('hide'); 
$('#myModal').data('bs.modal',null); // this clears the BS modal data
//...

// now works as you would expect
$('#myModal').modal({backdrop:'static', keyboard:false});