Flash-vesions of sof- and elf-file not usable?

I used the NIOSII_processor_booting_an370 guide

(option 2) to combine an elf- and a sof-file into a

pof-file. I put the pof-file into flash and the application

ran o.k.

However, when I programmed the sof- and elf-file

separately I got this error when downloading the

elf-file:

--

Verify failed between address 0x18080000 and0x1808001F

Leaving target processor paused

--

Is it impossible to use sof- and the elf-file in this way

because of the changes necessary to put them in flash?

Thanks,

Jos