Nexus S downgrade with Clockwork Mod I have a Sprint Nexus S 4G running ICS Cyanogenmod 9.  I want to run 2.3.6.

In CWR I've backed up, wipe/erased, wiped Calvik cache, but when I go to install my Sojus 2.3.6 file I get Installing update, Installation aborted.

I don't know why and I feel like I'm missing something obvious.

One thing I noticed about the 2.3.6 package sojus-gwk74-factory-4a34b67a.zip is that in it there is image-sojus-gwk74.zip which is the largest file and what I put on the Nexus S' SD card. 

There is also radio-crespo4g-d720sprkh1.img and bootloader-crespo4g-d720sprke1.img which I didn't put on the SD card (or maybe I did, but I can't see them from the install from zip section).

Is there something else I am supposed to do with those files? Perhaps I am supposed to run fastboot before I go to recovery mode in CWR?

Model Number:
Nexus S 4G

Android Version:
4.0.4

Baseband version:
D720SPRLC1

Kernel Version:
3.0.31-cyanogenmod-ga64c18e  android@thebeast #1

Build Number:
IMM76I

Mod Version:
Apex v1.1.2

My problem is the exact same as this guy's: http://forum.xda-developers.com/showthread.php?t=1429669
You have to use fastboot.

That is all.

This is from my command line command history:

532  ./fastboot-mac flash bootloader bootloader-crespo4g-d720sprke1.img

533  ls

534  ./fastboot-mac reboot-bootloader

535  ./fastboot-mac flash radio radio-crespo4g-d720sprkh1.img

536  ./fastboot-mac reboot-bootloader

537  ./fastboot-mac flash recovery recovery.img

538  ./fastboot-mac flash boot boot.img

539  ./fastboot-mac flash system system.img

540  ./fastboot-mac flash userdata userdata.img

541  flashboot erase cache

542  ./fastboot-mac erase cache

543  ./fastboot-mac oem lock`