Need help(Please look)!!!

[alether]

Hello.I updated my iphone 3gs ios 5.1.1 to baseband 06.15.00 and when i try to downgrade to 05.13.04 it gets bricked no wifi no blootooth no 3g no i imei or modem number . After a restore the phone is back to normal i can jailbreak again(wifi,3g,bloototh works!).My serial is xx013 so i can upgrade and downgrade without a problem i checked i have a new bootrom.On baseband 06.15.00 somehow i managed to unlock my iphone but battery just drains too fast (it doesn't even hold full day with light usage) after a new restore on baseband 06.15.00 my iphone doesn't unlock but battery holds just great.Please help i want to have unlocked and normal battery iphone 3gs.Thank you in advance.I tried all guides to downgrade my iphone but it doesn't work it gets bricked or it takes no effect.