[lug] Grub menu item to go back to BIOS?

[scott.herod at comcast.net]

Hello,

I've got a small tool that unpacks a bootable ISO onto a USB drive and installs GRUB for booting.  (Often the partition on the USB drive has an NTFS file system so I cannot use isolinux directly.)  A customer has asked if I can add a grub menu item which essentially says, "Tell the BIOS that this is not a bootable device and fall-through to the next device".  Does anyone know a way to do that?

More details:  I'm using grub4dos rather than GNU GRUB since my installer needs to run in Windows.  Grub4dos is very close to GRUB 1 in its command set.  I can do a "find" to see whether I can discover either /ntldr or /bootmgr and boot that from GRUB but that would potentially bypass a bootable CD that a user might have inserted.  I could also switch the root device to (hd1) and use the "chainloader +1" command but again that would probably bypass a bootable CD and I'm not sure that I can guarantee that (hd1) would be the next drive in the BIOS boot sequence or that it was bootable.

It would be best if there were a way to tell the BIOS that the USB device wasn't bootable and that the BIOS should move on to the next device in its list.

Thanks

Scott
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