Yes, some misunderstanding....

If common code is at 0, it is depending on the hardware to make it also appear at 10000.

It should not make identical code for 0 and 10000, it should make no code for 10000.

If the hardware does not do its job, and 10000 is different from 0, you will have some trouble, there is another thread discussing this.

The bottom line is, unless you have more experience, the hardware should make address 10000-17fff point address 0x0000-0x7fff