[Nexus S Q&A, Help & Troubleshooting] gsm city:
tried this method and files but when writing system.img showing failed.

C:\ADBFAST>fastboot devices
3531430F809D00EC fastboot

C:\ADBFAST>fastboot erase boot
erasing 'boot'... OKAY [ 0.047s]
finished. total time: 0.047s

C:\ADBFAST>fastboot erase cache
erasing 'cache'... OKAY [ 2.094s]
finished. total time: 2.094s

C:\ADBFAST>fastboot erase recovery
erasing 'recovery'... OKAY [ 0.031s]
finished. total time: 0.031s

C:\ADBFAST>fastboot erase system
erasing 'system'... OKAY [ 0.016s]
finished. total time: 0.016s

C:\ADBFAST>fastboot erase userdata
erasing 'userdata'... OKAY [ 0.016s]
finished. total time: 0.016s

C:\ADBFAST>fastboot flash bootloader bootloader-crespo-i9020xxlc2.img
error: cannot load 'bootloader-crespo-i9020xxlc2.img'

C:\ADBFAST>fastboot flash bootloader bootloader-crespo-i9020xxlc2.img
sending 'bootloader' (1536 KB)... OKAY [ 0.250s]
writing 'bootloader'... OKAY [ 0.359s]
finished. total time: 0.609s

C:\ADBFAST>fastboot reboot-bootloader
rebooting into bootloader... OKAY [ 0.000s]
finished. total time: 0.000s

C:\ADBFAST>fastboot flash radio radio-crespo-i9020uclh1.img
sending 'radio' (12288 KB)... OKAY [ 1.938s]
writing 'radio'... OKAY [ 1.844s]
finished. total time: 3.781s

C:\ADBFAST>fastboot reboot-bootloader
rebooting into bootloader... OKAY [ 0.000s]
finished. total time: 0.000s

C:\ADBFAST>fastboot -w update image-sojua-jzo54k.zip
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: I9020XXLC2
Baseband Version.....: I9020UCLH1
Serial Number........: 3531430F809D00EC
--------------------------------------------
checking product... OKAY [ 0.000s]
checking version-bootloader... OKAY [ 0.000s]
checking version-baseband... OKAY [ 0.000s]
sending 'boot' (3964 KB)... OKAY [ 0.672s]
writing 'boot'... OKAY [ 0.547s]
sending 'recovery' (4308 KB)... OKAY [ 0.719s]
writing 'recovery'... OKAY [ 0.609s]
sending 'system' (337599 KB)... OKAY [ 54.859s]
writing 'system'... FAILED (remote: Write Fail)
finished. total time: 57.422s

and when tried with 2nd file. now not able to erase userdata and system and at end system writing failed too.

C:\ADBFAST>fastboot devices
3531430F809D00EC fastboot

C:\ADBFAST>fastboot erase boot
erasing 'boot'... OKAY [ 0.000s]
finished. total time: 0.000s

C:\ADBFAST>fastboot erase cache
erasing 'cache'... OKAY [ 2.141s]
finished. total time: 2.141s

C:\ADBFAST>fastboot erase recovery
erasing 'recovery'... OKAY [ 0.047s]
finished. total time: 0.047s

C:\ADBFAST>fastboot erase system
erasing 'system'... FAILED (remote: Erase Fail)
finished. total time: 0.016s

C:\ADBFAST>fastboot erase system
erasing 'system'... FAILED (remote: Erase Fail)
finished. total time: 0.031s

C:\ADBFAST>fastboot erase userdata
erasing 'userdata'... FAILED (remote: Erase Fail)
finished. total time: 0.000s

C:\ADBFAST>fastboot flash bootloader bootloader-crespo-i9020xxlc2.img
sending 'bootloader' (1536 KB)... OKAY [ 0.266s]
writing 'bootloader'... OKAY [ 0.375s]
finished. total time: 0.641s

C:\ADBFAST>fastboot flash radio radio-crespo-i9020xxki1.img
sending 'radio' (12288 KB)... OKAY [ 1.922s]
writing 'radio'... OKAY [ 1.750s]
finished. total time: 3.672s

C:\ADBFAST>fastboot reboot-bootloader
rebooting into bootloader... OKAY [ 0.016s]
finished. total time: 0.016s

C:\ADBFAST>fastboot -w update image-soju-jzo54k.zip
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: I9020XXLC2
Baseband Version.....: I9020XXKI1
Serial Number........: 3531430F809D00EC
--------------------------------------------
checking product... OKAY [ 0.000s]
checking version-bootloader... OKAY [ 0.000s]
checking version-baseband... OKAY [ 0.000s]
sending 'boot' (3964 KB)... OKAY [ 0.641s]
writing 'boot'... OKAY [ 0.563s]
sending 'recovery' (4308 KB)... OKAY [ 0.734s]
writing 'recovery'... OKAY [ 0.609s]
sending 'system' (337443 KB)... OKAY [ 55.547s]
writing 'system'... FAILED (remote: Write Fail)
finished. total time: 58.141s

my nexus info

INFOproduct: herring
INFOserialno: 3531430F809D00EC
INFOversion-hardware: REV 11
INFOversion-baseband: I9020XXKI1
INFOversion-bootloader: I9020XXLC2
INFOsecure: yes
INFOunlocked: yes
INFOoff-mode-charge: 1
all:

help me what is going wrong?