Default [LG-Security] Error: Boot Image Signature!

Hi
I've been reading all the topics in here and trying many methods, but now im desperate, so i dediced to post here
When i try to run my phone the red text appears: [LG-Security] Error: Boot Image Signature!
I've tried to run http://forum.xda-developers.com/show...php?p=35971349 this guide, but when i plug off my battery i cannot get into s/w upgrade in my p880.
When the battery is plugged in I can run s/w upgrade, but my computer doesn't see the device.

Is the phone bricked?
Can i do anything to ressurect it?

EDIT:Problem solved - still don't know how, but after 5000th reboot it is just working without any other bugs etc...