This is a known issue with 3.07, it wipes your bootloader.
You either have to reinstall GRUB or if you’re lucky, it’s still there but EFI Boot Order has been reset:
If I recall correctly, that’s what happened in my case. I’m not dual booting but I installed the update via Windows running off an external drive. On reboot, it wanted to use the Windows bootloader off the external drive and since it was no longer there, failed to boot. I had to go into EFI Boot Order and find the entry for my Linux drive.
There’s mentions about how to reinstall GRUB earlier in the thread.