# Linux Mint won't boot



## pvtryan (Feb 24, 2010)

I'm dualbooting Win7 and Mint 10, each on their own disk. Mint will not boot. It was working fine a couple days ago, but now only Windows is working. 

When I tried to boot Mint recovery mode some of the last lines were:



> Gave up waiting for root device. Common problems:
> [here it listed four things]
> -
> -
> ...


I think that it could be a GRUB (GRUB 2) problem because when I booted up this morning GRUB did not have the 5-second timeout it was supposed to have. Minor things like this have happened to me in the past — once, by itself, it changed the default boot to memtest, and I had to change it back with the StartUp-Manager.

I would try using the StartUp-Manager or running sudo grub-mkconfig with my live CD, except that my live CD will not boot. The drive seems to be fine, because I just tested it with The Fellowship of the Ring.

The only thing I have changed recently (to my knowledge) is my CMOS battery, yesterday. Windows is working fine, and it can see the drive that Mint is on (meaning the drive IS connected and does exist!).

Thanks for the help.


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## hal8000 (Dec 23, 2006)

When you changed your CMOS settings, some of the BIOS settings mayb have changed to default.
Linux Mint (clone of Ubuntu) will use grub 2 and UUID to uniquely identify each hard drive partition. The partition will not have changed but may be a subtle change in one of the BIOS menues.

If you have award BIOS have a look in integrated peripherals. See if you have setting for
PCH SATA control mode. Default setting is IDE but if you change this to AHCI you will get better disk performance from a SATA drive and Linux Mint may boot.

If you use IDE drive look through other BIOS settings that may have changed.

WARNING. Changing IDE to AHCI may stop windows 7 from loading.

Without a working live CD this is going to be a difficult repair.


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## pvtryan (Feb 24, 2010)

I read something about changing SATA to AHCI and vice versa. I will try that, but I'm not even sure my crummy Acer BIOS has it.

I know it will difficult without a live CD...that's what I really want to fix. I have no idea why it would not be working.


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## pvtryan (Feb 24, 2010)

My BIOS does not have that option. By the way, it's an AMI.


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## pvtryan (Feb 24, 2010)

I was able to boot a live CD in compatibility mode just now. It gave me a command line. I ran "sudo fdisk -l" and it showed me that somehow my linux partition changed from sda1 to sdf1. I guess all I have to do is change GRUB.

I tried installing GRUB in the command line and running "sudo grub-mkconfig," but no dice.

How can I fix this via command line and why isn't the live CD working normally?


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## pvtryan (Feb 24, 2010)

I got both my live CD and my installation by adding 


```
irqpoll acpi=off noapic
```
to the kernel line.



Can someone please explain to me why I would need this now, when I did not need it before?

Also, I read somewhere that irqpoll takes a performance hit. Is there any way to fix this?

Thanks.


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## hal8000 (Dec 23, 2006)

The reason you need to use these grub parameters now:
irqpoll acpi=off noapic

is because something was altered in your BIOS when you changed the CMOS battery.
Some settings in BIOS are in permanent (non-volatile) memory but others are retained by the battery.


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## pvtryan (Feb 24, 2010)

Yes, but I changed all options in the BIOS back to what they were before I replaced the battery.


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