No IMEI and BASEBAND UNKNOWN:
Solution (It worked for me):
1. Flash your SGSII with Odin v1.85 with the following firmware: Hotfile.com: One click file hosting: I9100XEKDB.rar
2. Root your SGSII with: https://hotfile.com/dl/159843434/212...ecure.tar.html
3. On your phone, connect to WIFI, go to market or play store, and download the following files:
4. Install Busybox v1.17.1
5. Open GSII_Repair
6. Go to Repair GSII tab, follow the steps.
7. Your phone will reboot and you finally can see your IMEI and BASEBAND, now you are allowed to insert any SIM.