Problems about F12: Choosing first boot device.

[sddzcuigc]

Virutalbox4.1.2 on Win7
I used the vboxmanage to mount a usb device to usb.vmdk file and then attach it on a xp.vdi guest os.
Both of the usb.vmdk and the xp.vdi has loader programs.
usb.vmdk's mbr is covered with wee63.mbr(a grub4dos loader by tinybit) and xp.vdi's mbr is covered with nt52 loader(windows xp default).
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if usb.vmdk is primary ide controller master and xp.vdi is first ide controller slave.
Normally we thought it would boot from xp.vdi if we press F12 at start and chose the 2)primary slave.
but it turns out to be an error :"Remove disk or other media Press any key to restart".
if xp.vdi is primary ide controller master and usb.vmdk is first ide controller slave.
Normally we thought it would boot from usb.vmdk if we press F12 at start and chose the 2)primary slave.
But it turns out to be an error :"Urr! Wee..."
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Me English's bad.Asking Forgiveness and helpness.

[Sasquatch]

The problem is probably because they refer to disk0 (the first disk available) to look for further configs and instructions. Since they refer to the other disk for further instructions when you boot from it, things go bad. Nothing we can do about, nothing VB can do about either. Only solution is to make either disk look for disk1 for instructions. How to do that is outside the scope of this forum.

[sddzcuigc]

Thanks.