Question:
What is the address the boot vector is located at in the LPC9xx family? I see it is defined in Keil's start900.a51 file and located somewhere in the FFF0H - FFFFH range. Is that it?
Answer:
No, it isn't located at any address. Locating some of the special registers such as the boot vector, status bit, etc. at FFF0H and above is a convenience created by Keil. Flash Magic takes that hex record and converts it into the hex records you see in the datasheet to program those values one at a time.
Note that the Boot Vector value in start900.a51 is ignored by Flash Magic as it is too easy to accidentally change it.