I have a MacBook Pro in dual boot Mac OS X / Ubuntu 12.04 (Precise Pangolin). When I boot it I have a rEFIt menu, and I can chose between Mac OS X and Linux. A few days ago I have updated Mac OS X from 10.7 (Lion) to 10.8 (Mountain Lion) using a .dmg image provided by my company. Since then when I select Linux in rEFIt it says:

No bootable device --insert boot disk and press any key

1. I have tried going to rEFIt partitioning tool. This is what I got:

As suggested in Mac OSX Mavericks update rEFIT broken I wanted to fix the issue the same way as AndrewM, but I don't have the option "MBR table must be updated".

1. Then I booted on Ubuntu 12.04 CD, chose repair broken system, chose root patition /dev/sda6 as this is where my Ubuntu file system is. I got a shell, but I don't really know how to repair the poblem since if it was just Windows dual boot. A GRUB update would solve the issue, but here I don't know where the GRUB 2 is installed.

Here are results from Parted, and it is a bit confusing for me as the Mac partition is the one with boot:

As you can see the entry 1 is an EFI system partition and is the boot partition, so I wonder if I should install GRUB there or in sda6, which is the Ubuntu filesystem.

I am not sure should I work on rEFIt shell or Ubuntu. Unfortunately, I don't remember where GRUB was before update.

UPDATE: using same link above I have tried RoundSparrow hilltx answer and installed rEFInd, but the result is same.... still no bootable device when I select Linux.

UPDATE 2: just used alternate CD again, mounted on /dev/sda6 and the ran update-grub. It seemed to wok and started listing all my kernels. But after rebooting several times still no bootable device when I select Linux in rEFInd.

UDATE 3: Have tried to boot from Ubuntu cd and select "boot from first available filesystem. I got error and dropped to grub rescue shell. I even followed the indications on this link but was unable to boot as I tried to use sdb6 but no luck

UPDATE 4 as per Rob Smith request here is out put from ls -l $(find /EFI -iname "*.efi")

*MACOSX

-rw-r--r--@ 1 root  admin    55048 29 oct 17:44 /EFI/refind/drivers_x64/btrfs_x64.efi
-rw-r--r--@ 1 root  admin    38888 29 oct 17:44 /EFI/refind/drivers_x64/ext2_x64.efi
-rw-r--r--@ 1 root  admin    39304 29 oct 17:44 /EFI/refind/drivers_x64/ext4_x64.efi
-rw-r--r--@ 1 root  admin    43432 29 oct 17:44 /EFI/refind/drivers_x64/hfs_x64.efi
-rw-r--r--@ 1 root  admin    38984 29 oct 17:44 /EFI/refind/drivers_x64/iso9660_x64.efi
-rw-r--r--@ 1 root  admin    43656 29 oct 17:44 /EFI/refind/drivers_x64/reiserfs_x64.efi
-rw-r--r--@ 1 root  admin   175016 29 oct 17:44 /EFI/refind/refind_x64.efi
-rw-rw-r--  1 root  admin    73232  7 mar  2010 /EFI/tools/dbounce.efi
-rw-rw-r--  1 root  admin   763248  7 mar  2010 /EFI/tools/dhclient.efi
-rw-rw-r--  1 root  admin    67024  7 mar  2010 /EFI/tools/drawbox.efi
-rw-rw-r--  1 root  admin    71312  7 mar  2010 /EFI/tools/dumpfv.efi
-rw-rw-r--  1 root  admin    84848  7 mar  2010 /EFI/tools/dumpprot.efi
-rw-rw-r--  1 root  admin   472912  7 mar  2010 /EFI/tools/ed.efi
-rw-rw-r--  1 root  admin   143856  7 mar  2010 /EFI/tools/edit.efi
-rw-rw-r--  1 root  admin  1801008  7 mar  2010 /EFI/tools/ftp.efi
-rw-r--r--@ 1 root  admin    47848 29 oct 17:44 /EFI/tools/gptsync_x64.efi
-rw-rw-r--  1 root  admin   320560  7 mar  2010 /EFI/tools/hexdump.efi
-rw-rw-r--  1 root  admin   286384  7 mar  2010 /EFI/tools/hostname.efi
-rw-rw-r--  1 root  admin   534416  7 mar  2010 /EFI/tools/ifconfig.efi
-rw-rw-r--  1 root  admin   395344  7 mar  2010 /EFI/tools/loadarg.efi
-rw-rw-r--  1 root  admin   587408  7 mar  2010 /EFI/tools/ping.efi
-rw-rw-r--  1 root  admin   730416  7 mar  2010 /EFI/tools/pppd.efi
-rw-rw-r--  1 root  admin   561360  7 mar  2010 /EFI/tools/route.efi
-rw-rw-r--  1 root  admin  1961712  7 mar  2010 /EFI/tools/shell.efi 
-rw-rw-r--  1 root  admin   750224  7 mar  2010 /EFI/tools/tcpipv4.efi
-rw-rw-r--  1 root  admin     4048  7 mar  2010 /EFI/tools/textmode.efi
-rw-rw-r--  1 root  admin   320656  7 mar  2010 /EFI/tools/which.efi

*LINUX