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