SC520 CDP: When I set the CFG1 switch to ON --> nb0 command says that bank not presen

[Alexander Melichenko]

Hello, Vipin!
I want to place the lstart16.abs file to BIOS flash memory (29F040-DIP). In
lstart16.asm I found that it necessary set the CFG1 switch to ON. But when I
run :
    z
    yi
    nb0
I see a message : bank not present.
When I set CFG1 to OFF the command "nb0" works fine :
changed to bank 0, 512 KB, Device 29F040

Would You help me?

Thank You.

     Alexander Melichenko.