Lpc2000

Hi folks... I'm coming from AVR land, (because of defective Atmel
silicon and looking at these LPC parts),  and see that writing 0x1fc 
with 0x87654321 (sector 0 ?) protects the flash from being read.

I am curious if this is actually documented by Philips or somewhere
else.

I cannot seem to find any references to it except on forums etc...

Thanks,
bob