[Soekris] NET5501 Boot Problem

[Eternity]

Hi!

I have a problem with a whole bunch of NET5501:s. I have read some posts 
with similar problems, but not exactly this, I think, so I post my 
problem:

On a Cold boot my CF Card is detected:

Pri Mas  CF CARD 1GB                     LBA Xlt 983-32-63  990 Mbyte

Then at boot:

GRUB Loading stage1.5.

GRUB loading, please wait...
Error 25

---

If I press ctrl-p, and at once in combios makes a "reboot" everything 
works OK, and GRUB can load correctly.

I have used lots of net5501 boxes with this distribution (same image file 
I write to the CF card) without any trouble at all. I have tried upgrading
BIOS to 1.33c version, but no change.

Any ideas? Could it be the flash card? Or some defect on these batch of
boards?

Regards,
Chris