Wouldn't 10 cents worth of EPROM be a suitable choice? First boot, it supports the least-common-denominator channels, and you run an application with a big clicky flag icon to specify the regulatory environment. The OEM could even run this before shipment since he knows where the device is being shipped to. If you move, or travel, run the program and click a different flag.

It's not unreasonable to expect the customer to know which country he currently resides in.