Jamroom updates - to overwrite own things
Using Jamroom
You're doing that wrong - you should never make any changes to the PHP scripts. This can all be done in the item_detail.tpl file and a custom form field.
So it looks like you already created the custom form field - so you're fine there.
What you need to do is create a template OVERRIDE - create this file:
jrAudio_item_detail.tpl
in your CUSTOM skin directory. Now Jamroom will use THIS file instead of the jrAudio/templates/item_detail.tpl file.
INSIDE that file change this:
{jrCore_item_detail_buttons module="jrAudio" field="audio_file" item=$item}
to this:
{if $item.audio_dl == 'on'}
{jrCore_item_detail_buttons module="jrAudio" field="audio_file" item=$item}
{else}
{jrCore_item_detail_buttons module="jrAudio" field="audio_file" item=$item exclude="jrAudio_item_download_button"}
{/if}
So if $audio_dl is NOT ON we
exclude the item download button.
This way you can upgrade the Audio module and never worry about your changes being overwritten.
Let me know if that helps.