# kernel rebuild "WARNING: Your system is probably unbootable"

## pjp

So, I rebuilt my kernel yesterday (with 'make oldconfig' for the 1st time). I've never seen this before, and I didn't find any answers here on the forums (or Google).  So my question is, why would the system suddenly be unbootable?  Is this just because I leave /boot unmounted until I need it?  Interesting that it doesn't check for Grub.

I'm not in the mood to reboot (and find out it doesn't work), so I'm hoping this is a common issue.

```
sh /usr/src/linux-2.6.24-gentoo-r8/arch/x86/boot/install.sh 2.6.24-gentoo-r8 arch/x86/boot/bzImage System.map "/boot"

In order to use the new kernel image you have just installed, you

will need to reboot the machine.  First, however, you will need to

either make a bootable floppy diskette, re-run LILO, or have GRUB

installed.

Checking for ELILO...No

Checking for LILO...No

Checking for SILO...No

Checking for PALO...No

Should I make a bootdisk? (y/N)

WARNING: Your system is probably unbootable now.  After correcting any

problems, rerun this script with the command `mkboot -i'.

make[1]: *** [install] Error 1

make: *** [install] Error 2
```

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## Jeffrey0

You typed "make install" instead of "make modules_install". "make install" can't be used together with GRUB, you have to copy the bzImage over manually.

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## MostAwesomeDude

You need to have /boot mounted.

As a fun consequence, now your /boot mount point is filled with kernel files.

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## skellr

It only checks for update-grub and grub-install. it's "unbootable" if it can't find them (both?). Not sure why it wont  print out the check for grub though.  If you manage your bootloader with another install/distro then it's fine to ignore. It's a post install check so make install really does 'install' the the kernel to /boot even with the error.

The question is why are you only seeing this now? Maybe a typo? "make modules_install" Vs "make modules install"  If you don't normally run the install target and just copy the image to boot manualy then it would be a good idea to check /lib/modules before a reboot. I don't think install alone will install the modules.

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## 96140

--Last edited by 96140 on Wed Sep 11, 2013 9:17 am; edited 1 time in total

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## pjp

 *Jeffrey0 wrote:*   

> You typed "make install" instead of "make modules_install". "make install" can't be used together with GRUB, you have to copy the bzImage over manually.

   Thanks... looks like I did "make && make modules install" instead of "modules_install".  Not sure why I did the "make &&" part.

I thought I made notes the last time I built a kernel, but didn't see them around.  That's done, so hopefully I'll see them next time.

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## pjp

Jeffrey0 appears to have been correct.  The first kernel booted, but networking wasn't working.  Networking was fixed after adding "new" support for the network card (despite that the old had worked just fine in the previous driver).

Thanks again.

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## mackerel

from the documentation that I have read, make oldconfig should only be used when upgrading a revision, but not a version ie a -r1.  I have found also that network drivers (and many other settings) have been removed when using make oldconfig.

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## pjp

I think I read a Gentoo doc that suggested a minor change was ok... 2.6.20 to 2.6.21, but yes, it implied that it would be bad otherwise.

The weird thing about the network issue is that my old driver was selected, it just wasn't recognized.

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## 96140

--Last edited by 96140 on Wed Sep 11, 2013 9:17 am; edited 1 time in total

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## pjp

 *nightmorph wrote:*   

> You got it backwards. If you use make oldconfig, it's for revisions, ie. -r1 to -r2. It's not a good idea to try it on point releases, i.e. .25 to .26.

  Yep, you're right.  I think this is the doc that inspired me to create the thread in the first place.

 *nightmorph wrote:*   

> Just be sure to read through the menus to double-check new, changed, or removed options.

  That was what I was hoping to avoid, unfortunately.  I don't really care about new items that aren't required, but it'd be nice to have a quick reference to options x, y & z which I was using and are no longer in the kernel.

 *nightmorph wrote:*   

> @pjp:
> 
> As someone else has suggested, make sure that your /boot partition is mounted and writable before attempting to install the kernel.

  I'll give it a try next time... I normally leave it unmounted, so that was what went wrong.

 *nightmorph wrote:*   

> As a side benefit, you can just change your kernel entry in grub.conf to "/vmlinuz". Now every time you use make install, you won't have to alter grub.conf; "/vmlinuz" is a symlink that always points to the last kernel installed. Nifty, eh?

  Yes, but what to do about the previous kernel?  I keep at least the previous kernel around for "safe mode" just in case the new one doesn't boot.

Thanks for the tips.

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## mackerel

 *Quote:*   

> 
> 
> Yes, but what to do about the previous kernel? I keep at least the previous kernel around for "safe mode" just in case the new one doesn't boot

 

I use vmlinuz.old, which is the last one compiled

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## pjp

Whoda thunk.  Thanks.

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## thomasa88

 *pjp wrote:*   

>  Yes, but what to do about the previous kernel?  I keep at least the previous kernel around for "safe mode" just in case the new one doesn't boot.

 

As the previous poster said there's vmlinuz.old. Even better are that they are just symlinks to vmlinuz-x.x.x-name-rev, so all old kernels remain. (Just remember to clean the boot partition once in a while  :Razz: )

Also on the making and installing of the kernel, I run this line:

```
make all modules_install install
```

(just running make equals make all)

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