I set the grub entry for memtest to read "Memtest86", as suggested by Eelco.
I run:
svn merge -c -33692 ^/nixos/trunk
And edited the change a bit.
svn path=/nixos/trunk/; revision=33734
the same as the usual nixos. I think this trivial change works;
I checked the grub.cfg output generated in the iso_minimal.
svn path=/nixos/trunk/; revision=33692
because it can be overriden choosing another memtest86.
As an effect of a change in nixpgks, the isos will include
memtest86 4.0a instead of memtest86+ 4.20, only because the
former is released later, and I deduce it should work better.
svn path=/nixos/trunk/; revision=33691