Steps i followed,
1. I downloaded the g12_v4_tools large zip file of more than 500Mb..
2. Extracted and found new HBOOT 7 and Official HTC ICS 4.0 leaked Chinese ROM
3. Installed HBOOT 7
4. Installed HTC ICS ROM (Both by renaming corresponding zip files to PG88IMG.zip and copying to SD Card Root and from bootloader , it gets automatically detected)
5. Booted into the Chinese Rom, All went well, booted fine,
6. Installed 4EXT Touch Recovery 1.0.0.5RC
7. Rebooted into Recovery
8. Wipe Data/Factory Reset
9. Wipe Cache
10. Wipe Dalvik Cache
11 Install From zip and i chose MIUI 2.8.3 zip
12. Reboot after installation