# GenKernel - Re-Compile Kernel using menuconfig

## gen2newbie

Hi,

I need to add some more networking support options to my Kernel to get Firestarter working. I know what the options are and am new to linux and compiling Kernels. I have a pretty vanilla Stage 3 Gentoo Install (Installed following the online docs with the GenKernel and Grub options).

I tried to do a genkernel --menuconfig which seem to work and compile the Kernel with my new options. It also seemed to replace my current Kernel in /boot/kernels (checked by looking at the date and time stamp).

I made no mods to Grub as it pointed to the right kernel and boot partition and root drive.

However, when I restarted Gentoo claims that /dev/hda3 isnt a valid root partition hence I could no longer boot!

Can some one please guide me through the steps for recompiling via genkernel and then also tell me where it puts all the new files etc and what I should check in GRUB to ensure the system will boot!

PS (I made a full system sector by sector backup copy so didnt loose my system as I restored it back!).

Thanks in advance

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## gentoo_dude

Make sure that your root filesystem support is built in the kernel and not as module.

So if you / is reiserfs, under filesystem select reiserfs built in.  Recompile the kernel and try again to boot from the new kernel.

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## DetectiveInspekta

How do you make a new kernel in genkernel that DOES NOT overwrite the existing kernel?

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## taipan67

I've never used 'genkernel', so this is just a theory, but i believe you should be able to build separate kernel's that don't over-write each-other by using the command :-

```
genkernel --menuconfig all
```

...& once in 'menuconfig', going to 'General setup' & editing the 'Local version' option to something meaningful - for example, i once built a kernel specifically to try out 'ati-drivers', & entered the string "-ati", without quotes, in the 'Local version' field (putting the hyphen at the front makes file-names easier to read).

This caused my modular drivers to be installed in their own, uniquely-named directory, & i'm guessing that, had i issued the 'make' commands so that they installed the kernel for me as well, instead of just building it, it too would've had a name with the same unique suffix.  :Cool: 

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## gen2newbie

Hi  reiserfs was enabled in the kernel build.

Not sure if I had to mod the grub.conf after runing genkernel.

I have tried to genkernel --menuconfig all -- install to see if that bodes better.

Thanks for the pointers thus far.

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## gentoo_dude

The reiserfs was just an example.  You have to know what type of filestystem your / is.  So make sure that you have support for the / filesystem built in the kernel.

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## gen2newbie

Figured out the command:

genkernel --menuconfig --install --udev all

the --menuconfig (brings up the Kernel config options for your kernel)

the --Install (does what it says Installs the kernel!)

the --udev (configures the kernel to support udev so your filesystem mounts again after boot)

all (not sure what that does but is required!)

Thanks

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## St. Joe

If you are using the newer 2.6.12 kernel sources you will notice that the --udev option is deprecated since it is now included by default. The following command is sufficient:

genkernel --install --menuconfig all

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