How to fix error 1015

[rusli]

are you sure about your bootrom before use redsnow use?
Hotfile.com: One click file hosting: iPhone3Gs_4.2.1_8C148_Custom.[iPhoneRock.Com].ipsw

Guide :
1. Connect your phone with PC and switch off
2. Open redsn0w and choose Original firmware.
3. If you have newboot just press “yes”
4. now click “Next”
5. Choose “Just Enter pwned DFU mode right now”
6- now click “Next” again “Next” and follow the screen.
* you can useb iReb for pwned DFU mode too.
After that open itunes and press “Shift + Restore” and choose custom firmware 4.2.1
it will finish very quickly
Once you update you firmware
1. Connect your phone with PC and switch off
2. Open redsnow and choose Original firmware
3. If you have newboot just press “yes”
4. now click “Next”
5. Choose Only “Install Cydia”
6. now click “Next” again “Next” and follow the screen.
If you r getting White Cydia Icon just switch of your phone and open redsnow choose Stock firmware 4.2.1 and choose the option “Just boot tethered right now” and click “next” again “next” then follow the screen then you will see the cydia.
Finally you can see your phones is with your old Baseband. now just you can install the ultrasn0w 1.2 from Cydia


3Gs Custom firmware link 4.2.1

http://forum.gsmhosting.com/vbb/f456/3gs-recovery-logo-stuck-solution-here-1191554/#post6855641