Holy crap, it finally happened. I'm going to play with this now. Something's very wrong here. I can see my new boot menu for a split second, the u-boot goes back to the "Internal MMC, Internal Flash" blah blah blah. Looking at the menu generation script, it's probably ITEM_USEATAG instead of ITEM_USETAG. And the included kernel is kernel-maemo, which means that because of my ext4 /home, I can't boot back until I flash back kernel-power. This isn't good. I've done 5 kernel flashes trying to figure this out.