Can't flash back to official ROM

[usib]

I've been trying to flash the original ROM from UTStarcom, without success: the RUU says "this upgrade not designed for this device". Another updater from UTStarcom gives "Error 100: Unable to communicate with the device".

This is consistent with the fact that I can only use the NoID RUU for flashing a kitchen ROM. I guess somehow the device got de-branded, but I am not sure what the RUU checks, what's the mechanism how it knows the ID.

Any way to get it back to the old AKU ROM now?