Thanks for quick reply. Here is output of flashing. I am using Indian fw which was working great for almost 2 months before I sold it.

c:\Program Files\Nokia\Flasher>flasher -f -F main.bin --erase-user-data=secure
flasher 3.12.1 (Oct 6 2011) Harmattan
WARNING: This tool is intended for professional use only. Using it may result
in permanently damaging your device or losing the warranty.

Suitable USB interface (bootloader/phonet) not found, waiting...
Found device RM-696, hardware revision 1601
NOLO version 2.3.6
Version of 'sw-release': DFL61_HARMATTAN_40.2012.21-3_PR_005
Sending ape-algo image (7096 kB)...
100% (7096 of 7096 kB, avg. 18432 kB/s)
Suitable USB interface (phonet) not found, waiting...
Ping attempt 1 (250 ms)
Server application: 1.7.2
Found product RM-696 rev. 1601
Server implements softupd protocol version 1.8

Battery level 78 %, continuing.
Erasing, this may take a while.
Erase done.
Image SW version DFL61_HARMATTAN_40.2012.21-3_PR_005
Image moslo not present
Image mmc not present
Image tar skipped
Image config skipped

Battery level 78 %, continuing.

image [state progress transfer flash speed]
---------------------------------------------------------------------
[x] cert-sw [finished 100 % 1 / 1 kB NA ]
[x] cmt-2nd [finished 100 % 95 / 95 kB NA ]
[x] cmt-algo [finished 100 % 789 / 789 kB NA ]
[_] cmt-mcusw [finishing 0 % 6050 / 6050 kB 2834 kB/s]
[x] xloader [finished 100 % 23 / 23 kB NA ]
[x] secondary [finished 100 % 94 / 94 kB NA ]
[x] kernel [finished 100 % 2714 / 2714 kB 2144 kB/s]
[x] rootfs [finished 100 % 1170162 / 1170162 kB 10130 kB/s]
ERROR: SU_GET_UPDATE_STATUS_REQ terminated with error code 1: Unknown error

image [state progress transfer flash speed]
---------------------------------------------------------------------
[x] cert-sw [finished 100 % 1 / 1 kB NA ]
[x] cmt-2nd [finished 100 % 95 / 95 kB NA ]
[x] cmt-algo [finished 100 % 789 / 789 kB NA ]
[f] cmt-mcusw [finishing 0 % 6050 / 6050 kB 2834 kB/s]
[x] xloader [finished 100 % 23 / 23 kB NA ]
[x] secondary [finished 100 % 94 / 94 kB NA ]
[x] kernel [finished 100 % 2714 / 2714 kB 2144 kB/s]
[x] rootfs [finished 100 % 1170162 / 1170162 kB 10130 kB/s]
Fetching error list:
========================================
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
MTC_NOS_READY not received
MTC_NOS_READY not received
MTC_NOS_READY not received
CMT RFS failed
[Pipe 7] Finishing in error state with status 1
========================================

ERROR: Failed to flash images

also while checking settings-->About product I found that it was slow, and asking to be closed. Check attachment.