- A separable power supply and thus none of the heating problems that plagues the GuruPlugs. My GuruPlug neither has a fan nor overheats, but other people seem to whine about these things incessantly
- Sound card with TOSLINK out
- Instead of 512 megs of NAND, it has 2 megs of SPI flash and a 2-gig microSD card inside
- It doesn't come preloaded with Debian
So let's say you want to put Debian on your DreamPlug. You do, of course, because running some other operating system is in poor taste, and you'd be embarrassed telling your friends. How do you do it? You can't use d-i.
Let me back up. In the onboard SPI flash, there is a copy of Das U-Boot. This is a fork of mainline U-Boot, with no complete and corresponding source available. To the casual observer, this might look like an egregious GPL violation, but, on the other hand, no one seems to know how to rewrite the SPI flash except from U-Boot itself, so if you happen to corrupt said flash, your plug is bricked and openocd can't save you. I would be happy to be proven wrong on this last point, but for not let's assume that you're screwed and unable to replace your boot loader with free software.
The next problem is the kernel, which lives on the microSD card. This is potentially free software, though I can't swear that complete and corresponding source code is available. What I can claim is that linux-184.108.40.206.tar.bz2 on Google Code will build a Linux that works on the plug. I will also point out that this doesn't match Linux 220.127.116.11 from kernel.org.
Some other time I should rant about ARM Linux but for now I will just say that if you use the U-Boot of questionable provenance and either the Linux that's shipped with the plug or the one at the above link, you will be able to boot a mostly Debian system. I'll mention the third exception later.
One thing you can do is to take the plug apart, remove the microSD card from its slot, and then stick it into a reader that you can then manipulate on another machine. If you're choosing this route and wish to take this opportunity to replace the microSD card with something larger than 2 gigs, keep in mind that you'll have to either preserve the uImage file from the first partition or build a new one.
I am not fond of cross-architecture anything. I prefer to do things natively rather than cross-compile or foreign-debootstrap, and I own enough armel boxes that I can do this easily. So at this point I would just debootstrap a new Debian base onto the second partition of the microSD card. The first partition contains the uImage (which is your Linux image in a wrapper), and must be a FAT filesystem since you can't replace your boot loader with something that can read a better filesystem. The second partition will be your rootfs and can be whichever filesystem your Linux can read.
If you do not have another armel system to play with, you might want to familiarize yourself with Marco's Sheevaplug instructions.
You can install to a USB stick as well. Just remember that U-Boot needs a FAT filesystem containing the uImage on it and that you can't use a kernel in Debian yet.
You'll also want to ignore the instructions regarding U-Boot, since that must be done differently.
I'll be back later with some more details.