Re: legacy-bios and uefi boot usb stick

[Pascal Hambourg]

Le 14/05/2017 à 11:44, John Frankish a écrit :
> I've made a couple of dual legacy-bios/uefi boot usb sticks using grub-2.00.
>
> Both of the usb sticks will uefi boot linux, but there appears to be a problem 
> with legacy-bios boot of linux.
>
> One of the usb sticks gives an "invalid partition table!" error

What displays the message ? GRUB or the BIOS firmware ? Do you get the 
GRUB rescue prompt ?
Some BIOS firmwares require that a primary partition has the boot flag.

> $ fdisk -l /dev/sdb
>
> Disk /dev/sdb: 62.2 GB, 62209916928 bytes
> 118 heads, 22 sectors/track, 46804 cylinders
> Units = cylinders of 2596 * 512 = 1329152 bytes
>
>    Device Boot      Start         End      Blocks  Id System
> /dev/sdb1               2       46000    59706702  83 Linux
> /dev/sdb2           46001       46804     1043592  ef EFI (FAT-12/16/32)

This looks like a very old version of fdisk. Cylinders are obsolete. Add 
-u to use sectors as unit instead.