Custom block template doesn't print content
Avoid short tags as not all servers support them.

Use:

&lt;?php print $block-&gt;content; ?&gt;


Instead of:

&lt;?= $block-&gt;content; ?&gt;


Also in block.tpl.php I would expect to see &lt;?php print $content; ?&gt; instead of $block-&gt;content.