It almost seems like a problem with the way that GRUB is reading the drive.
I say this because you can try to cat /boot/grub/grub.cfg and it's not reading out the right values. If you boot a USB stick while the drive is in AHCI mode, you can cat out those values using the kernel AHCI driver without troubles. For example: In AHCI mode, when the problem reproduces, run the following from the grub prompt: ls (hd0,msdos1)/boot ....grub can't find anything in the /boot directory at all in the majority of cases. If, by chance, you do happen to see a grub/grub.cfg file, running: cat (hd0,msdos1)/boot/grub/grub.cfg ...will read out garbage on the console. In ATA mode, where the system boots fine, at the grub menu, get to a grub prompt and run the same command. You'll see that grub *does* see a grub/grub.cfg and you can cat (hd0,msdos1)/boot/grub/grub.cfg successfully. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/741799 Title: OS fails to boot certain SATA drives in AHCI mode. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
