the binary form of the BCP file output is undocumented. So if all the BCP files you have are the binary(native) version you are up this creek without a paddle.
Ugh. Yes it looks like that's the creek I am on. Thanks Microsoft!
So, moving to another creek. It depends on the amount of data you are working with, but it might be worth it to spin up a VM in the cloud on AWS, Azure, etc that has SQL Server on it and import the BCP files there. You could then export the data using the character format instead of the native format:
Man that really sucks but if it's the only way then I guess it's the only way.
