So, it seems I get asked several times a day how to get the TMobile List theme back. After upgrading to 4.2.1 from 4.2.0 on the 8100 the TMobile List theme is changed from a list to a grid of icons. Many folks want the list back. Here is what to do:
On your BB:
Change the theme to any theme besides the TMo Zen theme.
On your PC:
1. Go to the following directory:
C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\8100-v18.104.22.168_P22.214.171.124\Java (note: the actual OS version folder may vary depending on which version of 4.2.1 you have installed)
2. Move the file net_rim_theme_100_240x260_b.cod into another folder somewhere (doesn't matter where, but if you save it somewhere else you can install it again later, if desired.) Just make sure it's removed from this folder.
3. Now connect the BB to the PC and run Application Loader. It should remove the above theme. The BB will then reboot.
4. Now download the following file and place it in the same directory as above. (We are essentially replacing the new theme with the old theme.) http://webpages.charter.net/john.cla..._240x260_b.cod
*Note: This file is a .cod but will download as a .zip file. Change the .zip at the end of the file name to .cod and replace as described above.
5. Now run Application Loader again and it should load the theme again. The BB will reboot once again. You should now have the list theme in the blue background TMo Zen theme.
(The method here is when you remove these .cod files from the java folder and then run application loader the DM says, ok, you don't want that .cod on the BB and will remove it. Likewise, when you add a .cod file to the java folder, if the .alx files allow, it will load the .cod back to the BB.)