I finally found it. kernel variables actually works.
But the prob is the other part of the upstream commit which we're reverting. The part which exports funny variables need not be reverted (and the di-hack.patch is not needed on top). But the first part, in showenv(), is needed. The difference is the `set' builtin. With our d-i hack/patches, `set' shows the fun variables. But without, it isn't. Unlike `env' which shows it either way. Bash behaves the same vay: it accepts and exports the funny variables, but it's `set' built-in doesn't show them. (Well, busybox's set shows only parts of the variable names, which seems like a bug, but it's a different story). So it looks lie we have, apparently, a single place in d-i which preseeds the debconf vars from environment and the preseed.cfg file, which uses `set', where it should be using `env' instead. And after fixing that place, everything should work. Where that place is? If anything, the DI_HACK is definitely not needed. Thanks, /mjt
