Lpc2000

SOMETHING is responsible for setting up the checksum.  It is done
automatically when using the Philips ISP programmer.  I don't know how
Keil does it but it should be documented somewhere.

Rowley does it by hard coding the constant in the device specific
startup code.  In my case this is Philips_LPC210X_Startup.s.

There is no getting around having a proper checksum if you want to
start the program automatically.

Richard