BE to Jessie cheat - Not Recommended unless you like danger.

[timber]

A few weeks ago I did an HE to Jessie upgrade and all is working very nicely but it's a big upgrade.

I wanted my (test) BE to also move to Jessie but didn't want to go through the long process of an upgrade from BE (Wheezy) to Jessie.
I recommend waiting until Jessie is stable and the BE to Jessie upgrade is fully documented and well tested.

With that said, this is how I did my BE to Jessie upgrade. (I like living on the edge sometimes and usually know how to fix things when they go wrong),
Caution, not for the faint of heart, I always have a live USB handy and know how to restore and update grub2.
(If you don't know exactly what you're doing, don't EVEN try this!) I have full backups of all partitions.

1) I coppied my (already upgraded to Jessie) HE-root partition using gparted then relabeled the copy to JessieBEroot.
2( Next I changed the UUID of JessieBEroot using tune2fs.
3) Then I used blkid to list all partitions so I could revise fstab file in JessieBEroot.(Both Root and Home partition UUID's needed to be changed to those of JessieBEroot partition and my existing (test) BEhome partition.
4) I also had to revise the UUID number in JessieBEroot grub.cfg so it would boot. (Not recommended changing this file but it's the only way I know to boot a partiton where the UUID number has been changed).

5) Next I booted to liveUSB and reinstalled grub2 to my favorite install then booted the HDD to that install and updated grub2.
Note: User name was the same for my original HE install as for my BE install or I would have needed to change /home/user of BE Home Partition to that of my original HE.
6) Next I booted into JessieBEroot and did an update-grub from there to make sure my grub.cfg was revised.

The process worked fine but there's a lot of potential to really mess things up so don't try this unless you really know what you're doing, have full backups of everything and are willing to pull your hair out if it doesn't work for you.

Doing this didn't take near as long as a normal upgrade from Wheezy to Jessie but it requires knowing the steps and what to do ... not if/ but when ... things go very wrong.

Dave

[mhwelsh]

Grubbing.
A technique which I use is as follows;

Often, sometimes, you loose your grip on grub and I use a usb version of 'Supergrub'.
This enables, providing you have usb start up in your bios, to select the system you wish to start from, if there is a choice, and it will start that system.
From there try

Code: Select all

cd /dev/disk/by-uuid
ls -al >/home/yourhome/dpkgldate.txt

.
This will list all of the actual uuid numbers.
Check and rewrite /etc/fstab (as root).
As root;
update-grub - hope fully this will give you information about other bootable partitions.
grub-install - dont forget the location of the mbr.
Now, with luck and a following wind you can restart with a selection of bootable partitions.
Remember you will have to edit fstab in all of the other systems this can be done from the first one if you have the other partitions included in your file manager.

Pitfalls;
If you try to start one of the partitions that has not had its uuid corrected the start up will stop half way. To get it going again you will need a Ctrl+D.
You may have to remount some partitions. These are highlighted by having zero contents when 'displayed' in the file manager.

I hope this helps somebody,
Happy New Year,

martin welsh

[timber]

Hi mhwelsh,

I'll have to check out 'super grub2 usb", sounds like a useful tool.
Never used it before.
Thanks for the information.

Dave

[excollier]

I can second the use of 'Super Grub 2 usb'. I also have it on a cd and Rescatux is another good one (Super grub 2 included).
I used it last week when I put Salix onto a computer as a dual boot with KWheezy. Salix uses LILO not Grub, and rather than go through tweaking LILO to try and include KWheezy, I rebooted with Super Grub 2, booted KWheezy and re-installed grub from there - quick and easy, now Salix is in the grub list like you'd expect.
Excellent tool, will boot Windows too.