How to change FM/AM Radio channel or tuner?

In the process of using, you may be meet FM/AM Radio doesn’t your country channel, like this problem:
AM radio seems to be tuning for euro channel spacing.
How do I change the regional settings for North America?
so how to solve it?
The SKU have include this GS, JY and KD, the UI like

You can do it like this steps:
First, open setting, click factory settings.

Second, enter password word:126

Third, find radio band and change the channel America1 or America2, then click apply