So, all udebs were available in the debian-ports server, so I decided to run the d-i image build process. It all worked fine, until there was a segfault by mklibs.
What's mklibs? It's basically a script that does a similar job of ldd and creates a minimal list of shared libs for the d-i image.
I found -and eventually fixed- a bug in mklibs-readelf, which caused it to segfault -I actually find it strange that this bug wasn't found before, as I could also reproduce it on amd64 and Ubuntu armel. Anyways,
patch send and I'm now proceeding with the rest of the d-i build process.
More later.