Here is the fix to restore the lock back to previous builds
1. Download and install Crackutil
2. Download Lock.cod file net_rim_bb_ribbon_app.cod
3. Unzip and drop the net_rim_bb_ribbon_app.cod file in the directory C/Program Files/Crackutil
4. Right click on Crackutil desktop icon, and select "Run as Aministrator"
5. Select FILE MANIPULATION - INTERMEDIATE
6. Select Load File to Device
7. Navigate to and select net_rim_bb_ribbon_app.cod
8. Let the phone reboot and your lock problem is fixed.

For those of you having problems with Crackutil, here is the alternate way. Try using this method. It was how to fix it before the crackutil was discovered. Now keep in mine this is re installing you OS, so for safety, back up your phone.
1. Make a backup of data with D.M
2. Must have your OS installed on computer and phone
3. Go to C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\9530-v4.7.0.141\Java
4. Delete net_rim_bb_ribbon_app.cod
5. Plug in phone and run loader it will remove mms from phone, phone will restart with an error that's OK just leave it sit that way and up plug from usb
6. Go back to C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\9530-v4.7.0..141\Java
7. Copy the net_rim_bb_ribbon_app.cod file in the directory
8. Plug phone back in run loader phone will update and install that cod and restart.
9. After phone restarts go to D.M and restore backup then send host routing table
10. Pull battery put battery back phone restarts
11. Lock Button should work as it did in previous builds.

This works for 9530 and 9500!!!!


I have read that some Vodafone users have had problems with it reverting back after plugging the phone into DM. This can be fixed easily by copying the above net_rim_bb_ribbon_app.cod in the directory path C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\9530-v4.7.0.141_P4.0.0.174 and highlighting the java folder and selecting paste. Then select overwrite.


NOTES:

1. Vista users make sure you install Crackutil as Administrator and change Compatability to Run this program as an administrator.

**Disclaimer**
If you do not feel comfortable with ANY of these steps DO NOT ATTEMPT, as this is altering you OS and can brick your phone...