Comment 23 for bug 1456443

I see two options here:
- use preseed rules to load block-modules dynamically when doing the network installation (since you're trying to do an automated install).
*or*
- get back to the kernel team and make it clear that you need the modules in *mmc-modules* rather than *block-modules*, in which case once the package is available we can do a d-i update to pull it in.

In the meantime, installing should already work, just you need to load the package yourself, either manually or though the preseed rules.