I think your issue may have been in partitioning the SD card. The netinst image IS ITSELF bootable. What you need to do is: dd if=netinst.iso of=/dev/sdb ...That is, write the ISO directly to the whole device, rather than to a partition. See the instructions at http://www.debian.org/CD/faq/#write-usb. If that doesn't work, check to make sure your machine can actually boot from an SD card.
I tried what you said, unfortunately no dice.
I think the machine *can* boot from an SD, since the developer published some .img files [1] to install debian unstale / Ubuntu. I notice they are .img files, while the one I dd'd is an .iso. Does that mean something?
Do you think it's polite to ask the debian-arm (devel) mailing list?
How can I get a meaningful output on why the thing refuses to boot from SD?
[1] http://www.powerdeveloper.org/platforms/efikamx/linux