nmrpflash fails to cross build from source, because it strips with the
build architecture strip via "install -s" during make install. Beyond
breaking cross compilation, this also prevents -dbgsym packages from
being emitted and makes DEB_BUILD_OPTIONS=nostrip useless. The easiest
way to fix this is to not strip and defer all stripping to dh_strip. I
suggest making the install command substitutable upstream.
dh_auto_install will pass a non-stripping install command and this fixes
all of the mentioned problems. Please consider applying the attached
patch.

Helmut