Lpc2000

I have problem with MEMMAP register in LPC2138.
By default MEMMAP register is equal to 0x00.
In this mode during the code execution after the reset vector next
address is 0xFFFFD1BC.
In order to not remapping memory this register should be equal to 0x01.
I'm using IAR EWARM soft.
In which part of code should I change value of this register?
Should it be cstartup.s78 file?

best regards
Hubert