# How to configure the default kernel in FreeBSD 12.0



## Rajesh (Feb 13, 2019)

Recently, I tried installing a custom kernel on FreeBSD 12.0.  Seems, with FreeBSD 12.0, all available kernels gets auto-detected (listed in loader menu). But how shall we set the default kernel to boot from (so that I don't need to choose the kernel manually everytime)?  

With FreeBSD 11.2, if we set the "kernel=<name>" in loader.conf, then it will be listed in the loader menu as the first kernel (default kernel). But, with FreeBSD 12.0, seems the newer kernels are ordered sequentially backwards. Setting "kernel" in loader.conf, doesn't seem to have an impact.  Any clue?

Also, with FreeBSD 12.0, sometimes I observed the crashdump getting collected properly(vmcore and info files), but the "core.txt.N" file not getting created. Any reasons?


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## T-Daemon (Feb 13, 2019)

Rajesh said:


> With FreeBSD 11.2, if we set the "kernel=<name>" in loader.conf, then it will be listed in the loader menu as the first kernel (default kernel). But, with FreeBSD 12.0, seems the newer kernels are ordered sequentially backwards. Setting "kernel" in loader.conf, doesn't seem to have an impact. Any clue?


I can not reproduce the problem. Setting kernel=“<name>” in /boot/loader.conf brings the specified kernel as first (default) in the loader menu on my 12.0 system.  Check for possible other kernel settings in /boot.


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## Rajesh (Feb 14, 2019)

Looks like we need the double quotes now.  If I set kernel name within quotes, default kernel is taking up.  I believe, this is not the case with 11.2.

Regarding the core.txt file not getting created, I see the following message during boot



> /dev/stdin:1: Error in sourced command file:
> Cannot access memory at address 0x65657246
> /dev/stdin:1: Error in sourced command file:
> Cannot access memory at address 0x65657246
> Unable to find matching kernel


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## Rajesh (Feb 19, 2019)

Any clue about the error messages posted above during core.txt generation?


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