o2 operator logo problem on Nokia 6230

I'm using Nokia 6230 cellphone. I would like to know that how can i remove my operator logo. I used to have a blank operator logo on my 6230 that worked fine, until one day i found when i turned off my phone and switched it back on it was no longer blank. The blank logo turned into a little question mark in a yellow box in the middle of the screen. So, can any body tell me that how to resolve o2 operator logo problem on Nokia 6230? Any body knows about it? Kindly help me out to resolve the above issue.

Operator logo must be in .bmp format. For that you need to upload that file onto your phone and using MobiMB while the file is highlighted, right click and SET AS --> OPERATOR LOGO, that will replace the operator logo. If you do want it back, just use the Setting/Display Settings/Operator Logo and turn it off.

The easiest way to remove previously downloaded operator logo and restore the original one is to send almost normal operator logo message to the phone. You could back up the phone using the pc suite and then flash the latest firmware on the phone.

You need to check the filename according to your network/country. First you have to download the operator logo then if u go to Menu-->Settings-->Display Settings-->Operator logo you can switch on or off the operator logo. Another solution by restoring original phone settings under the settings menu. That may had change your operator logo.