creating device nodes?

Okay, I'm stumped. I can create /dev/fb1 and run omapfbplay etc. On one SD card, /dev/fb1 is there every time I start up, and on every other card it disappears at every reboot. As far as I know, the mknod procedure was the same on all of them. I've noticed that /dev is mounted on tmpfs, so where do I look to configure the device nodes?

I've tried creating it under /media/mmcblk0p2/dev, and it stays, but doesn't show up in /dev

I found device_table, and they are identical between cards, according to diff.

uname -v reports the same kernel build time between working and not working cards.

If you are using the angstrom demo:

rm /etc/dev.tar

That will invalidate the udev cache for coldplugging.