Re: No grub screen or boot after upgrade to jessie [FIXED]
Robert S a écrit :
>
> (Excuse ignorance) How do you display whether a partition is bootable? It
> used to be easy with cfdisk, but I can't find the option in gdisk or the
> newer fdisk.
Your disk uses the new GPT partition format. You can display whether the
"legacy boot" flag for a GPT partition is set with gdisk and the "i"
command. However AFAIK this flag is not used.
Some broken BIOSes require that a partition in the legacy partition
table located in the MBR have the boot flag set to boot a disk. On a GPT
disk, you can change this flag using parted and the "disk_set pmbr_boot"
command. It should still be possible using the "-t dos" option to force
fdisk to work on the legacy partition table.
However, upgrading grub-pc is not supposed to have modified this flag,
and if it was not necessary for the BIOS to boot that disk before, it is
not necessary after. Besides, BIOSes generally print an error message
such as "no bootable device found" instead of just a blank screen.
See also <http://www.rodsbooks.com/gdisk/bios.html> which contains
valuable information about booting in BIOS mode from a GPT disk.
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