GRUB2 hangs on boot from floppy

[Sergey Matveychuk <sem@ciam.ru>]

Hello!

I've made a floppy as described in README file.
It start booting with message:
PUPA loadind kernel

clears screen and hangs with three flashed color chars in random positions.

When I press a reset button I can't boot with BIOS beeping. I need to 
turn off my computer on a few seconds and turn on again for the normal 
operation.

I have Epox 8RDA3+ motherboad with nForce2 Ultra400 chipset. Builtin 
ATA133 controller and two Maxtor disks.

Need you more info about my hardware?

I've build GRUB2 on FreeBSD. But I've write core.img on my floppy I've 
got this message:

# dd if=core.img of=/dev/fd0 bs=512 seek=1
dd: /dev/fd0: Invalid argument
41+1 records in
41+0 records out
20992 bytes transferred in 1.038010 secs (20223 bytes/sec)

I've tried different floppy disks to be sure they are good. With all of 
them I've got that message.

# ls -la boot.img core.img
-rwxr-xr-x  1 root  wheel    512 Mar 16 10:10 boot.img
-rw-r--r--  1 root  wheel  21256 Mar 16 10:11 core.img

It looks like dd can't write full core.img? Why?
How can I fix it?

(GRUB1 boots well for me)
-- 
Sem.