GRUB Hard Disk Error

[Jozsi Vadkan]

I've got two pendrives.

I want to install a Debian on them. RAID1.

Ok...

...

After I installed it in RAID1, it works perfectly, ok! :)

When I pull out one of the pendrive [good pendrive], it still boots up,
hurrah :)

But: ...

When I pull out the other pendrive [i plug in the first one i tried] it
say's:

GRUB hard disk error

What can I do?

I already tried:
grub-install /dev/sdc <-that's the pendrive name [bios -> hard drive
emulation=hard drive, not auto]

or:
# grub
find /boot/grub/stage1
hd0,0
hd1,0

root (hd0,0)
setup (hd0,0)

etc.

What's the solution? Please help me:\

I can't just dd the first 512 Byte of the "good pendrive", because the
uuid is stored there. [needed for the sraid..]

It gets to the grub, so it's not a ""boot-order problem""

How can I install grub to these two pendrives, so that if one of the
pendrives die, it would still be a bootable system?