i used xs++
and europe w610 mbn.
but i get this
13:37:41| Hold 'C' button on phone and connect phone NOW.
13:37:41| You have 30 seconds...
13:37:41|
13:37:41| Baseband ID: 9900
13:37:41| Protocol Version: 3.1
13:37:41| Warning: IMEI name does not match GDFS name (IMEI:Z520 GDFS:W610)
13:37:41| ...using IMEI name
13:37:41|
13:37:42| Profiling SEMC phone...
13:37:42| Platform: DB2020
13:37:42| OTP CID: 51
13:37:42| EROM CID: 52
13:37:42| EROM Color: Red
13:37:42| IMEI: 35715401xxxxxx
13:37:42| Phone ID: Z520
13:37:42| Region: EUROPE_1
13:37:42| CDA: CDA12345678/123 R2A
13:37:42| Firmware Version: R1KG001
13:37:42| EROM: R3A022
13:37:42| Ready for operation!
13:37:49|
13:37:49| Sending db2020_cid01_prodid_p3j.bin...
13:37:49| Applet ID: 070129 0950 NGUCXC1250330_DB2020_PRODUCTIONIDLOADER_P3J
13:37:49| This is a PRODUCTION_ID loader
13:37:49|
13:37:49| Sending db2020_mem_patcher_cid52_r2a006.bin...
13:37:50| Applet ID: 061205 1523 HANCXC9876543210_DB2020_MEM_PATCHER_R2A006 0
13:37:50| This is a MEM_PATCHER loader
13:37:50|
13:37:50| Sending db2020_cid52red_flash_r2a005.bin...
13:37:50| Applet ID: 061201 1314 HANCXC1329129_DB2020_FLASHLOADER_R2A005
13:37:50| This is a FLASH loader
13:37:50| Now flashing firmware main...
13:37:50| Flashing c:\documents and settings\abbu\my documents\w610_r8ba024_main_generic_na_red53.mbn
13:37:50| Header type: BABE
13:37:51| 460 flashblocks
13:37:51| Binary acknowledge failed with: 89
13:37:51| Failed
13:37:51| Binary acknowledge failed with: 68
13:37:51| Command: Error 0x68
13:37:51| Failed sending flashblock 1. Returnvalue 0xD0022D00
13:37:51| Finishing flash
13:37:51| Binary acknowledge failed with: 02
13:37:52| Failed
13:37:52| Failed

13:49:02| Sending db2020_cid01_prodid_p3j.bin...
13:49:02| Applet ID: 070129 0950 NGUCXC1250330_DB2020_PRODUCTIONIDLOADER_P3J
13:49:02| This is a PRODUCTION_ID loader
13:49:02|
13:49:02| Sending db2020_mem_patcher_cid52_r2a006.bin...
13:49:03| Applet ID: 061205 1523 HANCXC9876543210_DB2020_MEM_PATCHER_R2A006 0
13:49:03| This is a MEM_PATCHER loader
13:49:03|
13:49:03| Sending db2020_cid52red_flash_r2a005.bin...
13:49:03| Applet ID: 061201 1314 HANCXC1329129_DB2020_FLASHLOADER_R2A005
13:49:03| This is a FLASH loader
13:49:03| Now flashing firmware main...
13:49:05| Flashing c:\documents and settings\abbu\my documents\w610_r8ba024_main_generic_na_red53.mbn
13:49:05| Header type: BABE
13:49:05| 460 flashblocks
13:49:05| Binary acknowledge failed with: 89
13:49:05| Failed
13:49:05| Binary acknowledge failed with: 68
13:49:05| Command: Error 0x68
13:49:05| Failed sending flashblock 1. Returnvalue 0xD0022D00
13:49:06| Finishing flash
13:49:06| Binary acknowledge failed with: 02
13:49:06| Failed
13:49:06| Failed

you cant flash z520 to w610 try to flash z520 back if it dosnt work you have to rewrite gdfs i hope you have an backup of it otherwise your phone is crap...

or if u dont have a backup gdfs u will need to send it to service