Can't boot from Ubuntu partition after upgrading to Yosemite

Question

When i go to Disk Utility the Ubuntu partition appears as it always have, i had installed since Mavericks refind to boot from any partition. Now refind doesn't work and the alt/option key doesn't work either. Does anyone know a way to fix this?

Answer 1

A extensive report already written is in the Ubuntu stacks as
Dual boot Linux and Yosemite
Basically you need to follow http://www.rodsbooks.com/refind/yosemite.html
wherein it explains that Yosemite is using a new LVM bootup from within the Recovery Partitions 10.10.
This messes up REFIT/REFIND tools  which have previously installed Partition 1.S
See my current Table below , wherein << are my comments
Current GPT partition table:
#      Start LBA      End LBA  Type
1             40       409639  EFI System (FAT)    << old preferred site for REFIT/REFIND tools
2         409640    154061023  Mac OS X HFS+ << main Mac partition
3      154061024    155330559  Mac OS X Boot  << Recovery 10.10 , installed by Yosemite update, used to start MAC boot.  BUT is not shown by Disk Utility, to prevent its naive deletion which would kill the MAC boot.
4      155330560    156598271  Mac OS X HFS+ << old Recovery 10.9, simply retained
5      157869786    228772129  Unknown << My Ubuntu partition
6      228772130    236765969  Linux Swap << which was shortened by 200 MB to make room for 7)
7      236765970    236974814  Mac OS X HFS+ << installation site of REFIND.  Though 4) could have been used, there is a possibility that Apple might have future plans for this small 4) partition.  
With 7) created (see detail below),  my REFIND install command under MAC, within Downloads/refind-bin-0.8.3/ was:
sudo ./install.sh  --alldrivers --ownhfs  /dev/disk0s7
There was still required the edit if refind.conf.sample specified in Yosemite.html, which I named refind.conf.edit1
This was copied with:
sudo cp refind.conf.edit1  /Volumes/macefi/System/Library/CoreServices/refind.conf
macefi  is my name for the MAC  /dev/disk0s7 mount point, equivalent to /dev/sda7 under Linux
CAREFULLY do read Yosemite.html,  as the instructions here are too terse by themselves!!!!
There are 2 routes to  boot Ubuntu, and then creat 7) with GPARTED
a) If you can access the GRUB shell under an old REFIT/REFIND installation, partitions will be shown by:
grub> ls
Presence of a Linux file system can be confirmed by a command like:
grub> ls (hd0,gpt5)/
Output of
grub > ls (hd0,gpt5)/boot/grub/
should include a grub.cfg file.  Then you can boot as usual with
grub > configfile  (hd0,gpt5)/boot/grub/grub.cfg
After boot up, start GPARTED
b) Alternatively boot with the Ubuntu install disk, and choose the Demo option
Open a text console, and get admin proviledge with:
$ sudo su
# gparted
Using GPARTED, unmount if necessary  any terminal SWAP partition, such as my 6) above
Then shrink the SWAP partition end by a trivial 200 MB,
Create a HFS+ partition in like my 7) for a coming REFIND installation
Note, that a file /etc/fstab contains a SWAP partition specification, which should be edited for automated SWAP start.
# sudo blkid  /dev/sda7
will report the SWAP space specs LONG  uuid code.  This can be copied into memory by dragging the mouse over the uuid
Then SHIFT-CONTROL-C  will copy it into memory.   Start an edit with:
$ sudo nano /etc/fstab
delete the old swap uuid, and paste in the replacement with
SHIFT-CONTROl-V
and swap should mount upon reboot, or with:
$ sudo swapon -a
Check with:
$ free
which should report none-zero swap space.