flash image from SD card

[Neng-Yu Tu (Tony Tu)]

> 
>> - if the u-boot we use at the factory is the same we ship the devices
>>  with, we could just not replace it. So, do we really need a separate
>>  version for use inside the factory ?
> 
> I'm definitely leaning towards that option.
> If we have to have 2 u-boot versions, I want to REALLY understand why 
> that is so.
> Wolfgang
>

Factory has add some test code in the u-boot and has different 
configuration for modules.

For example, factory u-boot default GSM power is ON, so they could 
download GSM frimware and at final station write IMEI. Also they have 
different default value in USB charging/power testing item.

Again, any change in production software need extra verification with 
current test item and test plan in factory.

Tony Tu