The file updmap is intended to be edited when you add some Type 1 fonts to
TeX. It seems to me that qualifies it for a %config marking. So that
upgrading tetex-dvips won't lose any changes. (Again.)
And yes, I had to remove japanese.map from updmap besides adding my own
maps to it. Otherwise dvips dumps core, as explained in bug 32134 and
others. But this is a different issue, though related of course.
This defect is considered SHOULD-FIX for Fairfax.
Fixed in 1.0.7-27.