[Q] Invalid CG Version (CG: boot) topic

Hi everyone:
I followed the following steps but failed:
1. Go and download moto-fastboot here (fastboot command from sdk will work too)

2. Download boot.img from here and put it in the folder with moto-fastboot
SHA1: 4add80cb4d5d54bc382ac1cb5c9bed3602853dce (same as in 2.3.6)

3. Boot your moto in FlashBoot mode (vol up + vol down + power)

4. Open command prompt and go to the above folder

5. Check if your device is present : moto-fastboot.exe devices

6. Next type: moto-fastboot.exe flash boot boot.img

You should see:
sending 'boot' (8192 KB)... OKAY [ 0.760s]
writing 'boot'... OKAY [ 1.455s]

I only can see this:
C:\temp1\boot>moto-fastboot.exe flash boot boot.img
sending 'boot' (8192 KB)... OKAY [ 0.767s]
writing 'boot'... INFOPreflash validation failure
FAILED (remote: )

Please help me. thanks