# [SOLVED] Can't boot gentoo

## JKosta

Hello!

When I try to boot gentoo I get an error message.

If I use root=UUID=d903f1cb-573a-47c8-8b52-df930e354689 in the kernel line of file /boot/grub/grub.cfg I get: Unable to resolve root: UUID=d903f1cb-573a-47c8-8b52-df930e354689.

If I use root=PARTUUID=0001cf5c-02, I get: 0001cf5c-02 is an invalid root device.

If I use root=/dev/sda2, I get: /dev/sda2 is an invalid root device.Last edited by JKosta on Mon Jul 28, 2014 9:51 pm; edited 1 time in total

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## The Doctor

Can you please provide some information about the setup?

I take it you have a disk, and it is partitioned where sda2 root (/)

What other partitions do you have? Is this in EFI mode? Are you using GPT or MBR partitions? What type of file system is root? Is this a genkernel or a manual one? Is grub turning control over to the kernel?

From what information you have here I would guess that your root is an exotic file system that grub can't read or you are missing file system support in your kernel.

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## JKosta

You're right sda2 is the root (/). 

```
$ blkid

/dev/sda2: UUID="d903f1cb-573a-47c8-8b52-df930e354689" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-02" 

/dev/sda1: LABEL="windows" UUID="8810BF6110BF5542" TYPE="ntfs" PARTUUID="0001cf5c-01" 

/dev/sda10: UUID="28717a34-7d74-4c51-96f4-f49486336165" TYPE="swap" PARTUUID="0001cf5c-0a" 

/dev/sda5: LABEL="fedora" UUID="415d2d38-9dc1-4ef6-8187-d50560bbfd10" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-05" 

/dev/sda6: LABEL="arch" UUID="c8ccbb27-a0ce-47f1-9a46-636cfc731cd8" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-06" 

/dev/sda7: UUID="1b03c950-d78f-486f-89c7-2814262c55fa" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-07" 

/dev/sda8: UUID="4d772572-2116-4b9e-b61d-8301008f9bd5" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-08" 

/dev/sda9: UUID="d38b85e4-836a-4f67-8013-ef8bf0dc3370" TYPE="ext4" PTTYPE="dos" PARTUUID="0001cf5c-09" 

/dev/sdb1: UUID="38d75e93-8bf6-480d-bb71-b9c9db7beb8d" TYPE="ext4" PARTUUID="90909090-01"
```

This is not in EFI mode. MBR partitions. 

I mixed. I ran make; make modules_install. Then I ran gemkernel --install initramfs.

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## The Doctor

Okay the mixing the kernel like that might be the problem. It is perfectly possible to do, but there might be some assumptions built into the initramfs that aren't true.

What does grep EXT4 /usr/src/linux/.config show? CONFIG_EXT4_FS should be built in since it is your root file system.

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## JKosta

```
$ grep EXT4 /media/gentoo/usr/src/linux/.config

CONFIG_EXT4_FS=y

CONFIG_EXT4_FS_POSIX_ACL=y

CONFIG_EXT4_FS_SECURITY=y

# CONFIG_EXT4_DEBUG is not set
```

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## JKosta

I recompiled the kernel using the command "genkernel all" and right now I'm answering you within my gentoo box.  :Very Happy: 

Thank you very much!

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## The Doctor

I'm not an expert in genkernel, but my guess is that the initramfs was trying to load a module that didn't exist. This is just speculation.

If you want to try manually configuring your kernel, may I recomend the instructions on this site? The seeds are old, but the advice is timeless. http://kernel-seeds.grytpype-thynne.org/working.html

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## JKosta

Thank you for your suggestion.  :Wink: 

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