Sorry for messaging on this topic but I am having kind of similar issues. I have Dir 882 A1 US 1.30 variant router I have looked every where for Dir 882 A1 russian variant unencrypted file to migrate from US to RU russian firmware. I am not sure if this is something possible. But as it seems you have more experience on this. Can you please tell me if you have any firmware which can help me to do this? I have already tried firmware ru 4.1 through emergency flash but that did not worked out 
both firmware re made from different sources
they use different boot loaders and are incompatible with each other
you can do it but there is a lot of risk
They carry same chipset model. But I could not found an unencrypted version of file. which will allow me to flash RU model firmware.... I am ready to take the risk. But I just don't know how or where to begin.