Alright, we have Registry Edits on the brain ever since our How To article went up. Here's a combo How To with a side of optional registry edit:

In our forums, coppertop asks about how to set up an MP3 as a ringtone on a BlackJack II. Here's a hint: the way you do it is annoying and not intuitive at all. Save your mp3 wherever you like. Now here's the wonky part. The BlackJack II has two file browsers - the default one from Windows Mobile and another one called “My Stuff.” Use “My Stuff” and navigate to your mp3. When it's highlighted, one of your menu options is to set it as a ringtone. It will prompt you to move the file to your /My Documents/My Sounds folder -- but it really means “copy,” FYI. Done!

Now for the registry edit. By default, the BlackJack II doesn't allow for MP3 ringtones over 300kb. That's awfully small - so the fix is, you guessed it, changing that setting in the registry. Per CycleNC:

Go into HKEY_Current User → ControlPanel → Sounds
Delete the key of FileSizeLimit

Done. Now, you've applied the GPS Hack too, right? Your BlackJack II is on its way to custom heaven.