Thomas and Erik, thanks for the info. Since I need a totally unused block of 8k flash that may be totally erased, LJMPs from the 0x0000 vector base are not a solution. As a workaround I'm using a linker command to 'skip' block 1 for code use:

CODE(0x0000-0x1FFF, 0x4000-0xFFFF)

CSEG is still at 0x0, the vectors stay where they are and I have the 8k block I needed.

Thanks again.