Update for SD and micro SD cards: For larger than 2GB cards, using a small boot directory has been necessary. I have successfully set up micro SD cards with grub this way, booting from a card reader. I have, however, not been able to boot from a smartphone (Android 2.2) using the same card. Running Knoppix off the card in the phone works, though.

I have found legacy grub very handy for such hardware, but haven't tried grub4dos so far. The boot partitions at the end of the sector list does not seem to interfere with ordinary use of the card in cameras, phones etc. One of the really practical things with grub, is that I can add multiple entries to accomodate different boot configurations.

Beware of drive designations when using cards in multiple card readers!