# Not able to boot from the Updated Kernel

## manu_leo

Hi Experts, 

I recently upgraded the kernel version from 3.17.7 to 4.1.15. Soft link fro /usr/src/linux now points to this new kernel linux-4.1.15-gentoo-r1. I then copied the old kernel config to the new one using 

 *Quote:*   

> cp /boot/config-3.17.7-gentoo /usr/src/linux/.config 

 

Then rebuild my .config  file using :-

 *Quote:*   

> cd /usr/src/linux
> 
> make silentoldconfig
> 
> 

 

The /boot location has 

 *Quote:*   

> config-3.17.7-gentoo     
> 
> System.map-3.17.7-gentoo.old
> 
> config-3.17.7-gentoo.old  
> ...

 

I am now stuck here. When I reboot my server, it still boots using the old kernel which is expected because I donot see any entry for vmlinuz-4.1.15-gentoo-r1. How can I get this fixed. 

Need your expert advice as to how to get this fixed. Appreciate all your help in future.

Thanks.

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## massimo

Did you take a look at Kernel Upgrade?

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## manu_leo

Thanks for looking into it, I did followed the exact same link.

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## massimo

So did you build the kernel and copy it over to /boot and did you also modify your boot manager's configuration file, e.g., /boot/grub/grub.cfg?

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## manu_leo

Thanks Massimo, I did build the kernel and copied it over to /boot location. However I am not really sure how to modify the /boot/grub/grub.cfg file to make this new kernel as the default one and keep the old kernel as well as a Failover option.

Appreciate all your help.

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## massimo

You can generate a new grub.cfg using grub2-mkconfig, e.g.,

```

# grub2-mkconfig -o /boot/grub/grub.cfg

```

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## Buffoon

I name my new kernel bzImage and my old kernel bzImage.old, never need to reconfigure GRUB.

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