You need to adapt the prm file to only use the 0x1500..0x16FF area for READ_ONLY segments.
However note that if the boot loader does not cover the reset vector, then it will be possible to lose the target board if your target loses power while just reprogramming the vectors at 0xFFFE. I think the only way to program a reliable boot loader which is to place it below 0xFFFE
(as consequence of this it makes it necessary to implement some interrupt vector redirection, but that's the price to pay for the reliable boot loader.)
Daniel