Nios 5.1, elf2flash ignores base address?

Ahhh - you've answered what my question should really have been (i.e. has Altera decided to change SREC addresses from absolute to relative).

I don't use nios2-flash-programmer, I use my own handwritten one. I just needed to add a single line of code to fix it, and I'm now happy in the knowledge that Altera aren't going to release a "fix" in a few weeks that would break it.