[TheLastSuperman]

Actually you could just run a query, quite a few different variations of said query to just remove this "word or phrase". I'm not sure but if I recall correctly Joe's mod prevents it from time of install forward (maybe that would explain why it didn't work like you assumed it would OR I could be assuming wrong here lol).

This would replace the text in your main forum i.e. the one with ID #1:

UPDATE post
LEFT JOIN thread ON post.threadid = thread.threadid
LEFT JOIN forum ON thread.forumid = forum.forumid
SET pagetext = replace( pagetext, 'Sent from my', '' ) 
WHERE forum.forumid = 1;

^ So you could remove per forum.

This query here could remove per threadid:

UPDATE post SET pagetext = replace( pagetext, 'Sent from my', '' ) WHERE post.threadid = '123456';

I've used the top two queries they work just fine if you key in the correct forumid or threadid if doing single threads etc.

I suppose though you could do a very broad query such as (untested):

UPDATE post SET pagetext = replace( pagetext, 'Sent from my', '' );

Perhaps this:

UPDATE post SET pagetext = replace( pagetext, 'Sent from my iPhone', '' );

Be sure to run a database backup before attempting any queries if you're unfamiliar with how they work and/or what they can in-turn do!