mtk nand 6571 can not rebuild imei-help

Action : Repair IMEI
Tips:
1.Remove Battery, Insert usb cable, Insert battery
2.power off Phone, Remove & Reinsert Battery , insert USB Cable
(In Case Some Phone Required to hold bootkey)
Waiting for Phone Usb…
Phone found [ USB Port:COM109 ]
Connecting…
Connection Done.
Read CPU Info…
CPU_ID: 6571
CPU_SW: 0000
CPU_HW: CA00
uploading boot image to RAM…
Handshake received from Phone.
uploading boot image to RAM…
Handshake Received from Phone.
eMMC cid: 000000000000000000
CHIP : MT65710000
CPU ID :
NAND ID : 00AD00BC00900055
NAND Size: 512MB
NAND Name: Unknown Flash
Read Hardware Information is done.

Checking imei …

NAND Flash unsupport now.

Action completed
Time taken : 00:00:08
Reconnect Battery/USB Cable
CS-Tool Ver 1.38.15

help me